:XCOM: Enemy Unknown

File:XCOM Enemy Unknown, illustration of the combat UI.jpeg

XCOM: Enemy Unknown casts the player as the commander of an elite military organization who directs soldiers in turn-based combat missions against invading alien enemies. The player controls a squad of between one and six human soldiers or robotic units as they explore the game's levels. Most missions in the campaign occur on maps randomly selected from a handcrafted set; enemies are then randomly placed on these maps.{{cite web |url=https://www.shacknews.com/article/72737/the-procedural-world-of-xcom-enemy-unknown |title=The procedural world of XCOM: Enemy Unknown |first=Andrew |last=Yoon |work=Shacknews |date=March 6, 2012 |access-date=October 29, 2023 |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029045602/https://www.shacknews.com/article/72737/the-procedural-world-of-xcom-enemy-unknown |url-status=live}} Fog of war hides aliens and their actions from view until the player's soldiers are in range and have line of sight to them.{{cite web |url=https://www.vg247.com/xcom-enemy-unknown-multiplayer-chess-is-for-wimps |title=XCOM Enemy Unknown multiplayer: chess is for wimps |first=Dave |last=Cook |work=VG 247 |date=August 30, 2012 |access-date=October 29, 2023 |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029044100/https://www.vg247.com/xcom-enemy-unknown-multiplayer-chess-is-for-wimps |url-status=live}} Most missions require players to eliminate all threats in a map, though some require players to rescue civilians or extract a target. Players can choose to retreat and abandon the mission if the situation goes awry.{{cite web |url=https://kotaku.com/before-you-start-tips-for-playing-xcom-enemy-unknown-5949758 |title=Before You Start: Tips for Playing XCOM: Enemy Unknown the Best Way |first1=Luke |last1=Plunkett |last2=Hamilton |first2=Kirk |work=Kotaku |date=October 9, 2012 |access-date=October 29, 2023 |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029044059/https://kotaku.com/before-you-start-tips-for-playing-xcom-enemy-unknown-5949758 |url-status=live}} The game has four difficulty levels: easy, normal, classic and impossible.{{cite magazine |url=https://www.gameinformer.com/b/features/archive/2012/10/06/xcom-s-classic-ironman-mode-is-an-even-match-for-its-creator.aspx |title=XCOM's Classic Ironman Mode Is An Even Match For Its Creator |first=Adam |last=Biessener |date=October 6, 2012 |access-date=October 29, 2023 |magazine=Game Informer |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029044100/https://www.gameinformer.com/b/features/archive/2012/10/06/xcom-s-classic-ironman-mode-is-an-even-match-for-its-creator.aspx |url-status=live}} There is also an "ironman mode", which limits the player to one save.

On the player's turn, each squad member can perform a limited number of actions. After all soldiers have performed actions, the artificial intelligence-controlled enemy takes its turn. Soldiers can be instructed to move, attack or both, depending on their available action points. Other actions such as reloading, remaining in overwatch to shoot any moving enemy in the line of sight, healing, throwing grenades and using special abilities can also be performed. Attacking or dashing large distances across the map will immediately end a squad member's turn. The game's user interface informs the player of the possibility of landing a successful shot and the amount of damage they will deal.{{cite web |url=https://www.pcgamesn.com/secret-dice-rolls-xcom-enemy-within |title=The secret dice rolls of XCOM: Enemy Within. How Firaxis fudge the numbers |first=Steve |last=Hogarty |work=PCGamesN |date=October 15, 2023 |access-date=October 29, 2023 |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029044101/https://www.pcgamesn.com/secret-dice-rolls-xcom-enemy-within |url-status=live}} Squad members can take cover behind objects, reducing the chance of being hit. The amount of defense a squad member has is indicated by a shield icon. Full cover is indicated by a filled blue icon and half cover is indicated by a half-filled blue icon. A yellow-and-red shield shown to players warns they are being flanked or being completely exposed, respectively. Soldiers will sustain more injuries from attacks due to the lack of defense. Cover may be destroyed through missed shots or the use of explosives.{{cite web |url=https://www.gamedeveloper.com/design/overwatching-an-analysis-of-x-com-enemy-unknown |title=Overwatching: An Analysis of X-Com Enemy Unknown |first=Josh |last=Bycer |work=Gamasutra |date=November 20, 2012 |access-date=October 29, 2023 |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029044100/https://www.gamedeveloper.com/design/overwatching-an-analysis-of-x-com-enemy-unknown |url-status=live}}

As soldiers progress through the game, they earn experience and are promoted, allowing players to specialize them. As soldiers earn promotions, for each rank they gain, players can select one out of two perks, although on the ranks of Squaddie and Major, only one perk is available.{{cite web |url=https://www.eurogamer.net/x-com-enemy-unknown-preview-first-contact |title=XCOM: Enemy Unknown Preview: First Contact |first=Paul |last=Dean |work=Eurogamer |date=May 25, 2012 |access-date=October 29, 2023 |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029044100/https://www.eurogamer.net/x-com-enemy-unknown-preview-first-contact |url-status=live}} The game has four character classes, each with unique weapons, gadgets and abilities. The Assault class can attack after dashing; the Support class can heal teammates more effectively and provide additional support; the Heavy class wields a rocket launcher, and the Sniper class is equipped with a sniper rifle, allowing it to kill enemies from afar with a high critical-damage bonus.{{cite web |url=https://www.gamesradar.com/xcom-enemy-unknown-classes-and-abilities-guide/ |title=XCOM: Enemy Unknown classes and abilities guide |first=Matt |last=Hughes |work=GamesRadar |date=October 8, 2012 |access-date=October 29, 2023 |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029044100/https://www.gamesradar.com/xcom-enemy-unknown-classes-and-abilities-guide/ |url-status=live}}{{cite web |url=https://www.pcgamer.com/xcom-enemy-unknown-guide/2/ |title=XCOM: Enemy Unknown guide - squad builds, ET tactics, base-building strategy and more |first=Tom |last=Hatfield |work=PC Gamer |date=October 9, 2012 |access-date=October 29, 2023 |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029044100/https://www.pcgamer.com/xcom-enemy-unknown-guide/2/ |url-status=live}} Some soldiers may have access to psychic powers, allowing them to boost their team's willpower, reduce the enemy's combat efficiency, and briefly take control of enemy units. Classes are assigned randomly and cannot be changed. Each recruit's name and appearance can be customized.{{cite web |url=https://www.gamesradar.com/xcom-enemy-unknown-9-reasons-were-excited-tactically-frag-some-aliens/ |title=XCOM: Enemy Unknown - 9 reasons were excited to tactically frag some aliens |date=October 3, 2012 |access-date=October 29, 2023 |work=GamesRadar |first=Lucas |last=Sullivan |page=3 |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029044205/https://www.gamesradar.com/xcom-enemy-unknown-9-reasons-were-excited-tactically-frag-some-aliens/ |url-status=live}} Soldiers may permanently die once their health reaches zero if they are not saved in time.{{cite web |url=https://venturebeat.com/games/xcom-enemy-unknown-game-guide-tactical/ |title=The XCOM field commander's tactical guide to Enemy Unknown |first=Rob |last=Savillo |work=VentureBeat |date=October 16, 2012 |access-date=October 29, 2023 |archive-date=October 29, 2023 |archive-url=https://web.archive.org/web/20231029044100/https://venturebeat.com/games/xcom-enemy-unknown-game-guide-tactical/ |url-status=live}} Soldiers can experience panic during a mission, which can make the player lose control of that character for a turn.

The game has a multiplayer mode for one-on-one tactical battles. Players spend a points budget on assembling a squad of up to six humans, aliens, or a mixture of both. Weapons, armor and gadgets of human units are customizable. A simplified version of the single-player perk system is present. Alien units may not be customized but have the abilities of corresponding aliens types in the game's single-player mode.{{cite web |url=http://www.pcgamer.com/previews/xcom-enemy-unknown-multiplayer-preview/ |title=XCOM: Enemy Unknown multiplayer preview |date=August 16, 2012 |publisher=PC Gamer |access-date=October 12, 2012 |archive-date=October 17, 2012 |archive-url=https://web.archive.org/web/20121017075516/http://www.pcgamer.com/previews/xcom-enemy-unknown-multiplayer-preview/ |url-status=live}}

XCOM's underground headquarters is presented in a view dubbed the "ant farm".{{cite web|url=https://www.polygon.com/gaming/2012/4/11/2940663/reimagining-x-com-with-xcom-enemy-unknown|title=Reimagining X-Com with XCOM: Enemy Unknown|first=Brian|last=Crecente|work=Polygon|date=April 11, 2012|access-date=October 29, 2023|archive-date=October 29, 2023|archive-url=https://web.archive.org/web/20231029044323/https://www.polygon.com/gaming/2012/4/11/2940663/reimagining-x-com-with-xcom-enemy-unknown|url-status=live}} From this view, the player manages construction, manufacturing and research projects, and directs scientists and engineers to use resources recovered from missions. Some resources can be sold to other XCOM nations through the gray market.{{cite web|url=https://venturebeat.com/games/xcom-enemy-unknown-game-guide-strategic/view-all/|title=8 tips for saving the world in XCOM: Enemy Unknown|first=Rob|last=Savillo|work=VentureBeat|date=October 17, 2012|access-date=November 18, 2023|archive-date=November 18, 2023|archive-url=https://web.archive.org/web/20231118170149/https://venturebeat.com/games/xcom-enemy-unknown-game-guide-strategic/view-all/|url-status=live}} As the player progresses through the game, they unlock new weapons, armor improvements and technology to improve each recruit's efficiency. Performing interrogations and autopsies on captured aliens yields additional rewards.{{cite web|url=https://www.gamesradar.com/xcom-enemy-unknown-research-and-engineering-guide/|title=XCOM: Enemy Unknown research and engineering guide|first=Matt|last=Hughes|work=GamesRadar|date=October 8, 2012|access-date=October 29, 2023|archive-date=October 29, 2023|archive-url=https://web.archive.org/web/20231029044100/https://www.gamesradar.com/xcom-enemy-unknown-research-and-engineering-guide/|url-status=live}} It is also where recruits in the game rest, exercise and tend to their wounds.{{cite web|url=https://www.rockpapershotgun.com/xcom-enemy-unknown-preview-2|title=XCOM Remake: 8 Things I Dig, 6 Things I Worry About|first=Alec|last=Meer|work=Rock, Paper, Shotgun|date=March 6, 2012|access-date=October 29, 2023|archive-date=October 29, 2023|archive-url=https://web.archive.org/web/20231029044100/https://www.rockpapershotgun.com/xcom-enemy-unknown-preview-2|url-status=live}} A memorial wall to soldiers killed in action is also visible.{{cite web|url=https://www.rockpapershotgun.com/they-shall-not-grow-old-the-xcom-memorial|title=They Shall Not Grow Old: The XCOM Memorial|first=Alec|last=Meer|work=Rock, Paper, Shotgun|date=December 11, 2012|access-date=October 29, 2023|archive-date=October 29, 2023|archive-url=https://web.archive.org/web/20231029044102/https://www.rockpapershotgun.com/they-shall-not-grow-old-the-xcom-memorial|url-status=live}} A holographic view of Earth called the "Geoscape" allows the player to track situations around the world, order aircraft to intercept UFOs and dispatch soldiers to engage aliens on the ground. Which situations the player decides to respond to influences the panic level of XCOM's member nations: responding in an area decreases panic while ignoring an area causes a rise in panic and potential for the nation to pull out of XCOM. Once a nation decides to leave it will never rejoin, meaning players will have fewer funds for the rest of the game. The game will end If eight out of the sixteen Council nations decide to leave. Passive bonuses are provided; these are dependent on which continent the player chooses for a base location. The player can better detect alien activity by launching satellites and positioning them over territories of the 16 XCOM nations. Passive bonuses can also be obtained by providing satellite coverage over each Council nation in a continent.{{cite web|url=https://www.engadget.com/2012-06-21-a-tactical-discussion-with-xcom-enemy-unknown-producer-garth-d.html|title=A tactical discussion with XCOM: Enemy Unknown producer, Garth DeAngelis|first=Richard|last=Mitchell|work=Engadget|date=July 15, 2016|access-date=October 29, 2023|archive-date=October 29, 2023|archive-url=https://web.archive.org/web/20231029044100/https://www.engadget.com/2012-06-21-a-tactical-discussion-with-xcom-enemy-unknown-producer-garth-d.html|url-status=live}}

The game's campaign begins in early 2015 as a global alien invasion begins. Prior to the start of the game, a group of countries called the Council of Nations has banded together to create Extraterrestrial Combat Unit (XCOM), the most elite military and scientific organization in human history that is tasked with defending the nations from alien attack. The player assumes the role of the commander of XCOM and engages in a war against an extraterrestrial enemy with overwhelming technological superiority.

In March 2015, a series of extraterrestrial objects land in a major German city. A squad of four soldiers is sent to investigate the incident. Upon entering a warehouse, the squad finds a small, alien creature mind-controlling German soldiers. The squad is ambushed; all-but-one of the soldiers are killed before the area is secured. Alien attacks begin all over the globe.

After shooting down alien scout ships and securing the crash sites from surviving alien crews, as well as interdicting alien attempts to abduct human civilians for unknown purposes, XCOM obtains the corpses of various alien troops. Autopsies reveal all of these alien types have been genetically or cybernetically altered, which seems to indicate they are foot-soldiers for unseen leaders. XCOM's head of research Dr. Vahlen requests the capture of a live alien for interrogation, which involves the development of a weapon that can capture a live alien and the construction of a facility in XCOM's subterranean base to safely hold a live alien prisoner.

XCOM captures one of the alien troops and interrogates it, revealing vague information about another type of alien called the Outsiders, which are artificially-created, crystalline beings that are encountered aboard unidentified flying objects (UFOs) and appear to serve as pilots and navigators. Dr. Vahlen then requests XCOM capture an Outsider for study. An Outsider is captured and examined, revealing their exotic, crystalline structures behave in a manner similar to antennas, receiving a signal broadcast from an underground location on Earth. XCOM dispatches a team to investigate the signal, which is found to be coming from a secret alien base where experiments are performed on abducted humans.

XCOM develops a method for gaining entry to the alien base and assaults it. During the mission, the alien base commander is discovered to have psychic abilities but the soldiers defeat it. The commander's psychic communication device is recovered and reverse engineered. Tapping into the aliens' communications reveals a stealth Overseer spacecraft is patrolling above Earth. The craft is shot down and is found to hold an alien species that had not yet been encountered, as well as a strange psionic artifact. The newly discovered species, called Ethereals, have powerful psionic abilities.

Once the Overseer ship is shot down and the psionic artifact recovered, a massive enemy "Temple Ship" in low Earth orbit over Brazil reveals itself and starts causing earthquakes. The reverse-engineering efforts enable XCOM to unlock and develop latent psionic powers that are present in some humans, thus enhancing their human soldiers. The most powerful of these human psychic soldiers becomes the Volunteer, who uses the psionic artifact to tap into the aliens' psychic communication "hive", an experience that also increases his or her psionic strength, allows the Volunteer to attack and board the Temple Ship, and seek the Uber Ethereal, the leader of the alien invasion.

During the final battle aboard the ship, the Uber Ethereal reveals that, because of their failure to further improve their own race, the Ethereals have been experimenting on other species throughout the universe to identify a race that is mentally and physically strong enough to be "Uplifted". By allowing humans to slowly obtain their technology, the Ethereals allowed humans to evolve to a fuller potential and believe humanity may be the culmination of their search for the perfect species to prepare for "what lies ahead", a vaguely worded destiny they do not further describe.

After slaying the Uber Ethereal, the Temple Ship begins to collapse into itself, creating a black hole that would destroy Earth due to its proximity. The Volunteer urges the other XCOM soldiers to evacuate the doomed ship but stays behind, using the psychic gift to control the ship and fly it further from Earth, causing the ship to self-destruct.

File:Sid Meier 2015-02-25 (cropped 2).jpg, the founder of Firaxis and the creator of the Civilization series, provided consultation for the game.]]

Development of XCOM: Enemy Unknown commenced at Firaxis Games in early 2008 as a "very, very big budget" project with a team of 50 to 60 developers.{{cite web|url=http://www.eurogamer.net/articles/2012-03-06-firaxis-xcom-is-a-very-very-big-budget-game|title=Firaxis: XCOM is a "very, very big budget game"|date=March 6, 2012|work=Eurogamer|first=Wesley|last=Yin-Poole|access-date=October 12, 2012|archive-date=November 14, 2012|archive-url=https://web.archive.org/web/20121114141344/http://www.eurogamer.net/articles/2012-03-06-firaxis-xcom-is-a-very-very-big-budget-game|url-status=live}} XCOM: Enemy Unknown was developed independently of 2K Marin's XCOM, which was later rebranded as The Bureau: XCOM Declassified, and although the two games are set in different universes, the games' developers were in contact with one another.{{cite web |url=http://www.gamespot.com/xcom-enemy-unknown/previews/xcom-enemy-unknown-whats-new-whats-not-6364778/ |title=XCOM: Enemy Unknown: What's New, What's Not |last=Douglas |first=Jane |date=March 6, 2012 |work=GameSpot |publisher=CBS Interactive |access-date=October 12, 2012 |archive-date=July 26, 2013 |archive-url=https://web.archive.org/web/20130726071253/http://www.gamespot.com/xcom-enemy-unknown/previews/xcom-enemy-unknown-whats-new-whats-not-6364778/ |url-status=live }} Enemy Unknown was the first title Firaxis Games developed that did not feature the name of Sid Meier, who was not directly involved in the game's development.{{cite web|url=https://www.gameinformer.com/b/features/archive/2012/01/20/sid-meier-talks-xcom-enemy-unknown.aspx|title=Sid Meier Talks XCOM: Enemy Unknown|publisher=Game Informer|access-date=October 12, 2012|archive-date=September 18, 2012|archive-url=https://web.archive.org/web/20120918170903/http://www.gameinformer.com/b/features/archive/2012/01/20/sid-meier-talks-xcom-enemy-unknown.aspx|url-status=live}}{{cite web|url=https://www.gameinformer.com/b/features/archive/2012/01/30/civilization-and-the-future-of-strategy-games-an-interview-with-sid-meier.aspx|title=The Future Of Strategy Games: An Interview With Sid Meier|publisher=Game Informer|access-date=October 12, 2012|archive-date=October 8, 2012|archive-url=https://web.archive.org/web/20121008083709/http://www.gameinformer.com/b/features/archive/2012/01/30/civilization-and-the-future-of-strategy-games-an-interview-with-sid-meier.aspx|url-status=live}}

Being a fan of UFO: Enemy Unknown (1994), director Jake Solomon had repeatedly petitioned Firaxis' leaders to create a sequel since he joined the studio. In 2003, Solomon was given six months to lead a team and develop a prototype for an XCOM game. He and other programmers quickly wrote a game engine using assets from media such as Unreal Tournament. In this early demo, which used an extensive inventory-management system, players explored a large, open area and eliminated alien threats. Reflecting on this version of the game, Solomon said it was a "classic case of overengineering". Firaxis deemed the project "unenjoyable" and quickly shut it. Solomon continued to assist studio head Sid Meier on Civilization projects for four years until the studio decided to diversify its portfolio. While working on Civilization Revolution, Solomon was given another chance to develop an XCOM game.{{cite web|url=https://www.polygon.com/features/2013/1/31/3928710/making-of-xcoms-jake-solomon-firaxis-sid-meier|title=The Making of XCOM's Jake Solomon|first=Russ|last=Pitts|work=Polygon|date=January 31, 2013|access-date=November 18, 2023|archive-date=October 28, 2023|archive-url=https://web.archive.org/web/20231028103136/https://www.polygon.com/features/2013/1/31/3928710/making-of-xcoms-jake-solomon-firaxis-sid-meier|url-status=live}}

In early prototypes, Solomon envisioned the game as a remake of the first game in the XCOM franchise. Gameplay features such as fog of war, multiplayer, and cinematic cameras were already included. The programming team, who deemed the task impossible due to time constraints and the restraints of Unreal Engine 3, rejected his desire to include procedurally generated maps. In 2009, a vertical slice of the game was shown to other members of Firaxis. A cover system is absent from this version of the game. Players can freely move their units as long as they have enough "time units". While the development team was confident, it was met with a mediocre response within the studio. Some reviewers enjoyed its complexities but most of them did not understand the concept. Reflecting on the demo, art director Greg Foertsch called it "painful" but Solomon recognized his prototype was "more complicated" than the original, making the experience unenjoyable. As a result, the team decided to remake the entire game, abandoning materials they had developed over a year and a half. The game had one of the longest development cycles of a Firaxis game, which typically only took two to two-and-a-half years.{{cite web|url=https://www.digitalspy.com/videogames/a430388/the-making-of-xcom-enemy-unknown-how-firaxis-revived-a-classic/|title=The making of XCOM Enemy Unknown: How Firaxis revived a classic|first=Matthew|last=Reynolds|work=Digital Spy|date=October 14, 2012|access-date=November 18, 2023|archive-date=October 28, 2023|archive-url=https://web.archive.org/web/20231028103139/https://www.digitalspy.com/videogames/a430388/the-making-of-xcom-enemy-unknown-how-firaxis-revived-a-classic/|url-status=live}}

Solomon and his team then improved the game, which was given the working title Combat 2.0. The team decided to add a tile grid for squad movement.{{cite web |url=https://www.eurogamer.net/how-firaxis-saved-xcom-from-complete-disaster |title=How Firaxis saved XCOM from complete disaster |first=Chris |last=Bratt |work=Eurogamer |date=July 28, 2017 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103158/https://www.eurogamer.net/how-firaxis-saved-xcom-from-complete-disaster |url-status=live}} In an early prototype of the game, each soldier had one tactical value that determined how effective they were at offense and defense. This number was later separated into offense and defense, which were altered based on factors such as height advantage, cover, or being flanked.{{cite web |url=https://www.gamesradar.com/jake-solomon-on-his-journey-from-underqualified-graphics-programmer-to-master-strategist/ |title=Jake Solomon on his journey from underqualified graphics programmer to master strategist |first=Jeremy |last=Peel |work=GamesRadar |date=January 2, 2023 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103139/https://www.gamesradar.com/jake-solomon-on-his-journey-from-underqualified-graphics-programmer-to-master-strategist/ |url-status=live}} Firaxis held weekly meetings called "Mutator Mondays", in which all team members discussed the state of the game and introduced a modifier that would change gameplay for that week. Through these meetings, the studio attempted to improve the overall's game experience or discard existing systems that were detrimental to gameplay. Time units, angled cover, base invasion, and lines that help players visualize their ability to take a clear shot at enemies were removed from the game.{{cite web |url=https://www.gamespot.com/articles/xcom-enemy-unknown-dissecting-the-strategic-layer/1100-6390815/ |title=XCOM: Enemy Unknown - Dissecting the Strategic Layer |first=Kevin |last=VanOrd |work=GameSpot |date=August 10, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103137/https://www.gamespot.com/articles/xcom-enemy-unknown-dissecting-the-strategic-layer/1100-6390815/ |url-status=live}} Despite restarting development, the team did not want to completely overhaul UFO: Enemy Unknown and instead intended to modernize the gameplay experience. Gameplay was changed, such as giving soldiers the ability to use special skills, and limiting the maximum squad size to six. The developers experimented with a larger squad size but they felt this made each move less meaningful, and affected the game's momentum and pacing. According to DeAngelis, each combat mission should last around 20 minutes and more-lengthy missions should not exceed 50 minutes. According to Sid Meier, the game was designed to cater for fans of action games, real-time strategy games and role-playing video games.{{cite web |url=https://www.eurogamer.net/xcom-enemy-unknown-to-appeal-to-action-rpg-and-rts-gamers |title=XCOM: Enemy Unknown to appeal to action, RPG and RTS gamers |first=Robert |last=Purchese |work=Eurogamer |date=January 24, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103140/https://www.eurogamer.net/xcom-enemy-unknown-to-appeal-to-action-rpg-and-rts-gamers |url-status=live}}

The team deemed "permanent death, destruction and turn-based combat" the franchise's major pillars. The game was intended to be challenging,{{cite web |url=https://www.shacknews.com/article/73246/xcom-enemy-unknown-a-love-letter-to-x-com |title=XCOM: Enemy Unknown embraces gaming's 'renaissance of difficulty' |first=Jeff |last=Matas |work=Shacknews |date=April 10, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103136/https://www.shacknews.com/article/73246/xcom-enemy-unknown-a-love-letter-to-x-com |url-status=live}} but the team wanted it to be accessible to newcomers. As a result, an extensive-but-optional tutorial section was included at the beginning of the game.{{cite web |url=https://www.gamedeveloper.com/design/classic-postmortem-i-xcom-enemy-unknown-i-which-turns-5-today |title=Classic Postmortem: XCOM: Enemy Unknown, which turns 5 today |first=Garth |last=DeAngelis |date=October 9, 2017 |access-date=November 18, 2023 |work=Gamasutra |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103200/https://www.gamedeveloper.com/design/classic-postmortem-i-xcom-enemy-unknown-i-which-turns-5-today |url-status=live}} The team also wanted the game to be fair so, unlike the original game, aliens will not attack the player until they are revealed.{{cite web |url=https://www.vg247.com/xcom-enemy-unknown-more-tactical-than-original-says-producer |title=XCOM: Enemy Unknown 'more tactical than original', says producer |first=Dave |last=Cook |work=VG 247 |date=August 23, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103200/https://www.vg247.com/xcom-enemy-unknown-more-tactical-than-original-says-producer |url-status=live}} Solomon identified the series' strength as its ability to demonstrate consequences. A poor decision may lead to very tangible results, such as the loss of a soldier or a nation's support, or the failure of a mission. By introducing permadeath, the team hoped to invoke a sense of unnerving despair and recreating the tense atmosphere from the original game. Producer Garth DeAngelis further added that through these losses, the team created a "sense of fear reverberating through the entire experience".{{cite web |url=https://www.ign.com/articles/2012/10/04/will-you-try-xcom-enemy-unknown |title=Will You Try XCOM: Enemy Unknown? |first=Colin |last=Campbell |work=IGN |date=October 5, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103136/https://www.ign.com/articles/2012/10/04/will-you-try-xcom-enemy-unknown |url-status=live}} Regardless of the player's actions, Firaxis decided to not comment on them to avoid pushing players into performing certain actions or causing them to second-guess themselves.{{cite web |url=https://www.rockpapershotgun.com/xcom-enemy-unknown-the-final-chatdown |title=XCOM Enemy Unknown: The Final Chatdown |first=Alec |last=Meer |work=Rock, Paper, Shotgun |date=September 10, 2012 |access-date=November 18, 2023 |archive-date=February 5, 2023 |archive-url=https://web.archive.org/web/20230205135151/https://www.rockpapershotgun.com/xcom-enemy-unknown-the-final-chatdown |url-status=live}} Solomon said XCOM is "an unfeeling collection of systems" that induces stress in players by forcing them to recognize the game did not care if they make the correct decision.{{cite web |url=https://www.polygon.com/2018/1/11/16869202/mario-rabbids-best-games-2017-year-in-review |title=Mario + Rabbids inspired the creative director of XCOM to reevaluate the genre |first=Jake |last=Solomon |work=Polygon |date=January 11, 2018 |access-date=November 19, 2023}}

The game's strategic layer also went through multiple changes and was redesigned two years into the game's development.{{cite web |url=https://www.eurogamer.net/the-re-making-of-xcom |title=The re-making of XCOM |first=Wesley |last=Yin-Poole |work=Eurogamer |date=November 10, 2013 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028180707/https://www.eurogamer.net/the-re-making-of-xcom |url-status=live}} Solomon experimented with different gameplay ideas; it once included gameplay mechanics that were inspired by tower defense video games and card games. To illustrate the game's strategic management, Solomon and Meier built an XCOM board game using pieces from Risk. Meier wanted the game to be turn-based but Solomon wanted it to remain real-time. The two spent a weekend creating a prototype for each of their proposed versions; Solomon's proposal was chosen as the final solution. Initially, the base-management portion of the game was played from an isometric perspective, which created unintentional gameplay and visibility issues. The team then switched to a side-on view that was inspired by books of cross-sections and cutaways.{{cite web |url=https://www.gamesradar.com/xcom-enemy-unknown-interview-we-talk-artistic-inspirations-greg-foertsch/ |title=XCOM: Enemy Unknown interview and exclusive screens |first=Hollander |last=Cooper |work=GamesRadar |date=August 11, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103158/https://www.gamesradar.com/xcom-enemy-unknown-interview-we-talk-artistic-inspirations-greg-foertsch/ |url-status=live}}

Multiplayer had been intended as a part of the package since the project's inception. The team wanted players to feel like a "brilliant tactician" and believed the only way to achieve this was to have the player face other human opponents instead of competing against AI. Tabletop games inspired the multiplayer mode. Solomon described the mode as "straightforward" but "endlessly complex"; while its objectives were simple, the diversity of units meant that players cannot predict what strategy they will need to adopt in a match. The inclusion of multiplayer was initially controversial, though the team reiterated that it would only add to the experience without affecting the single-player mode. While the campaign only allows players to command human soldiers, the multiplayer deathmatch mode allowed them to control alien units directly.{{cite web |url=https://www.eurogamer.net/why-firaxis-xcom-remake-had-to-have-multiplayer-and-why-you-shouldnt-worry |title=Why Firaxis' XCOM remake had to have multiplayer, and why you shouldn't worry |first=Wesley |last=Yin-Poole |work=Eurogamer |date=August 10, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103137/https://www.eurogamer.net/why-firaxis-xcom-remake-had-to-have-multiplayer-and-why-you-shouldnt-worry |url-status=live}}

The developers, who were inspired by animals such as insects, spider monkeys and gorillas, wanted to modernize designs for some of the aliens from UFO: Enemy Unknown. The team first designed the Sectoids, the first alien species players encounter in the game and have been described a "classic big-headed alien" that were conceived as easily recognizable. Other aliens in later parts of the game had more outlandish designs. The Sectoids demonstrate more "animalistic" behaviors than they did in UFO: Enemy Unknown. The Mutons were designed to be physically imposing and ape-like;{{cite magazine |url=https://www.gameinformer.com/b/features/archive/2012/01/18/alien-breeds-the-evolution-of-xcom-s-enemies.aspx |title=Alien Breeds: The Evolution Of XCOM's Enemies |first=Ben |last=Reeves |magazine=Game Informer |date=January 18, 2012 |access-date=November 18, 2023 |archive-date=March 15, 2023 |archive-url=https://web.archive.org/web/20230315051701/https://www.gameinformer.com/b/features/archive/2012/01/18/alien-breeds-the-evolution-of-xcom-s-enemies.aspx |url-status=live}} the Chryssalids are now an alien quadruped with no humanoid characteristics; the Thin Men, who are infiltrators disguised as humans, are unnaturally slender and their design was inspired by human characters in the animated series Æon Flux. Other alien designs in the game were inspired by Men in Black and The X-Files.{{cite web |url=https://www.vg247.com/xcom-enemy-unknown-alien-designs-inspired-by-x-files-men-in-black |title=XCOM: Enemy Unknown alien designs inspired by X-Files, Men in Black |first=Brenna |last=Hillier |work=VG 247 |date=September 12, 2012 |access-date=November 18, 2023 |archive-date=November 18, 2023 |archive-url=https://web.archive.org/web/20231118051955/https://www.vg247.com/xcom-enemy-unknown-alien-designs-inspired-by-x-files-men-in-black |url-status=live}}

Plans to include large-scale aliens were scrapped. The Sectopods were originally intended to be a huge, hulking enemy but were significantly shrunk to ensure they can spawn in several of the game's levels instead of existing only as a setpiece. Designs that were scrapped include the Battletoad, which could pull soldiers out of their cover and eat them.{{cite web |url=https://www.ign.com/articles/2012/11/02/xcom-enemy-unknown-engineering-aliens |title=XCOM: Enemy Unknown -- Engineering Aliens |first=Anthony |last=Gallegos |work=IGN |date=November 3, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028180719/https://www.ign.com/articles/2012/11/02/xcom-enemy-unknown-engineering-aliens |url-status=live}} The design of XCOM's soldiers was inspired by action figures; the team strove for a stylized, bright, flat-textured look.{{cite web |url=https://www.polygon.com/gaming/2012/4/26/2979037/firaxis-xcom-soldiers-are-action-figures |title=Firaxis' 'XCOM' soldiers are action figures |first=Tracey |last=Lien |work=Polygon |date=April 26, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103140/https://www.polygon.com/gaming/2012/4/26/2979037/firaxis-xcom-soldiers-are-action-figures |url-status=live}}{{cite magazine |url=https://www.gameinformer.com/b/features/archive/2012/01/11/the-art-of-xcom-enemy-unknown.aspx |title=The Art Of XCOM: Enemy Unknown |first=Ben |last=Hansen |magazine=Game Informer |date=January 11, 2023 |access-date=November 18, 2023 |archive-date=June 2, 2023 |archive-url=https://web.archive.org/web/20230602062927/https://www.gameinformer.com/b/features/archive/2012/01/11/the-art-of-xcom-enemy-unknown.aspx |url-status=live}} Earth was chosen as the game's setting because it was relatable for players. The team juxtaposed recognizable locales with aliens to create an eerie atmosphere.{{cite web |url=https://www.rockpapershotgun.com/xcom-enemy-unknown-preview |title=Know Your Enemy: Firaxis On XCOM, Part 1 |first=Alec |last=Meer |work=Rock, Paper, Shotgun |date=February 1, 2012 |access-date=November 18, 2023 |archive-date=November 12, 2023 |archive-url=https://web.archive.org/web/20231112095729/https://www.rockpapershotgun.com/xcom-enemy-unknown-preview |url-status=live}}

Roland Rizzo, who has been working on the X-COM series since its inception, became the audio lead for XCOM: Enemy Unknown, and was tasked with re-imagining and updating John Broomhall's original music score. Rizzo replayed UFO: Enemy Unknown to better understand the music.{{cite web |url=https://www.gameinformer.com/b/features/archive/2012/01/16/the-unsettling-music-of-xcom-enemy-unknown.aspx |title=The Unsettling Music Of XCOM: Enemy Unknown |publisher=Game Informer |access-date=October 12, 2012 |archive-date=October 8, 2012 |archive-url=https://web.archive.org/web/20121008082036/http://www.gameinformer.com/b/features/archive/2012/01/16/the-unsettling-music-of-xcom-enemy-unknown.aspx |url-status=live}} Michael McCann was recruited to compose the game's musical score after the team heard his score for Deus Ex: Human Revolution. The soundtracks for the game are predominantly dark, synthwave music.

Game Informer revealed XCOM: Enemy Unknown on January 5, 2012.{{cite web |url=https://www.gameinformer.com/b/news/archive/2012/01/05/february-cover-revealed-xcom-enemy-unknown.aspx |title=February Cover Revealed: XCOM: Enemy Unknown |publisher=Game Informer |access-date=October 12, 2012 |archive-date=October 15, 2012 |archive-url=https://web.archive.org/web/20121015092027/http://www.gameinformer.com/b/news/archive/2012/01/05/february-cover-revealed-xcom-enemy-unknown.aspx |url-status=live}} Firaxis and publisher 2K described the game as a "reimagining" of X-COM: UFO Defense (1994).{{cite web |url=https://www.shacknews.com/article/71888/xcom-enemy-unknown-is-reimagining-of-1994-game |title=XCOM: Enemy Unknown is 'reimagining' of 1994 game |first=Steve |last=Watts |work=Shacknews |date=January 9, 2012 |accessdate=November 18, 2023 |archive-date=March 20, 2012 |archive-url=https://web.archive.org/web/20120320071601/http://www.shacknews.com/article/71888/xcom-enemy-unknown-is-reimagining-of-1994-game |url-status=live}} A playable demo of the game was available at E3 2012.{{cite web | url=http://www.ign.com/articles/2012/06/06/e3-2012-xcom-enemy-unknown-turn-based-alien-action | title=E3 2012: XCOM: Enemy Unknown – Turn-Based Alien Action | publisher=IGN | date=June 6, 2012 | last=Gallegos | first=Anthony | access-date=June 1, 2013 | archive-date=January 26, 2013 | archive-url=https://web.archive.org/web/20130126100338/http://www.ign.com/articles/2012/06/06/e3-2012-xcom-enemy-unknown-turn-based-alien-action | url-status=live }} Pre-ordering the game granted players access to an Elite Soldier Pack, which included the "Classic X-COM Soldier"—a haircut for the player's male soldier based on the model for troops in UFO: Enemy Unknown—and the option to customize the aesthetic design of soldiers' armor.{{cite web |url=https://www.polygon.com/gaming/2012/7/25/3187344/xcom-details-elite-soldier-pack-preorder-bonus |title=XCOM shows first images of Elite Soldier Pack preorder bonus |first=Tracey |last=Lien |work=Polygon |date=July 25, 2012 |accessdate=November 18, 2023 |archive-date=June 1, 2023 |archive-url=https://web.archive.org/web/20230601021856/https://www.polygon.com/gaming/2012/7/25/3187344/xcom-details-elite-soldier-pack-preorder-bonus |url-status=live}} Players who preordered on Steam also received bonus items for Valve Corporation's video game Team Fortress 2 and a free copy of Firaxis' 2010 strategy game Civilization V.{{cite web |url=https://www.polygon.com/gaming/2012/9/6/3299204/xcom-enemy-unknown-coming-to-steam-with-pre-order-bonuses |title='XCOM: Enemy Unknown' coming to Steam with pre-order bonuses |first=Tracey |last=Lien |work=Polygon |date=September 6, 2012 |accessdate=November 18, 2023 |archive-date=May 29, 2023 |archive-url=https://web.archive.org/web/20230529184901/https://www.polygon.com/gaming/2012/9/6/3299204/xcom-enemy-unknown-coming-to-steam-with-pre-order-bonuses |url-status=live}} XCOM: Enemy Unknown{{'s}} playable demo version was released in September 2012.{{cite web|url=https://www.pcgamer.com/xcom-enemy-unknown-demo-released/|title=XCOM: Enemy Unknown demo released|first=Marsh|last=Davies|work=PC Gamer|date=September 25, 2012|accessdate=March 7, 2023}}

XCOM: Enemy Unknown was released for Windows PC, PlayStation 3 and Xbox 360 in North America on October 9, 2012, and in Europe on October 12, 2012.{{cite web |url=https://www.eurogamer.net/xcom-enemy-unknown-release-date |title=XCOM: Enemy Unknown release date |first=Robert |last=Purchese |work=Eurogamer |date=July 26, 2012 |accessdate=November 18, 2023 |archive-date=October 4, 2023 |archive-url=https://web.archive.org/web/20231004085202/https://www.eurogamer.net/xcom-enemy-unknown-release-date |url-status=live}} An iOS port was released on June 20, 2013.{{cite web |url=https://www.pocketgamer.com/xcom-enemy-unknown/lead-designer-jake-solomon-reckons-xcom-enemy-unknown-for-ios-is-a-happy-acciden/ |title=Lead designer Jake Solomon reckons XCOM: Enemy Unknown for iOS is a 'happy accident' |first=Harry |last=Slater |work=Pocket Gamer |date=May 31, 2013 |accessdate=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103200/https://www.pocketgamer.com/xcom-enemy-unknown/lead-designer-jake-solomon-reckons-xcom-enemy-unknown-for-ios-is-a-happy-acciden/ |url-status=live}} Firaxis described the game's mobile release as a premium product.{{cite magazine|url=https://www.gameinformer.com/b/news/archive/2013/07/30/xcom-on-ios-proves-gamers-are-willing-to-pay-premium-price-for-a-premium-experience.aspx|archive-url=https://web.archive.org/web/20130801164417/http://www.gameinformer.com/b/news/archive/2013/07/30/xcom-on-ios-proves-gamers-are-willing-to-pay-premium-price-for-a-premium-experience.aspx|url-status=live|archive-date=August 1, 2013|title=XCOM On iOS Proves Gamers 'Willing To Pay A Premium Price For A Premium Experience'|first=Mike|last=Futter|magazine=Game Informer|date=July 30, 2013|access-date=March 7, 2024}}{{cite web |url=https://www.engadget.com/2013-06-17-xcom-enemy-unknown-ios-june-20.html |title=XCOM: Enemy Unknown invades iOS devices on June 20th |first=Ben |last=Gilbert |work=Joystiq |date=July 17, 2013 |accessdate=November 18, 2023 |archive-date=February 26, 2021 |archive-url=https://web.archive.org/web/20210226224206/https://www.engadget.com/2013-06-17-xcom-enemy-unknown-ios-june-20.html |url-status=live}} The team had to decrease the file size of the mobile version by decreasing the number of maps available and lowering texture resolutions. The mobile versions of the game were co-developed by 2K China.{{cite web|url=https://www.ign.com/articles/2013/04/08/xcom-on-iphone-and-ipad-will-have-no-paid-power-ups|title=XCOM on iPhone and iPad Will Have No Paid Power-ups|first=Justin|last=Davis|work=IGN|date=April 9, 2013|accessdate=February 12, 2024}} A version for Android was released on April 24, 2014.{{Cite news |date=April 24, 2014 |title=XCOM: Enemy Unknown is out now for Android devices |language=en-gb |work=Eurogamer.net |url=https://www.eurogamer.net/xcom-enemy-unknown-is-out-now-on-android-devices |access-date=June 11, 2022 |archive-date=June 11, 2022 |archive-url=https://web.archive.org/web/20220611062928/https://www.eurogamer.net/xcom-enemy-unknown-is-out-now-on-android-devices |url-status=live }} XCOM: Enemy Unknown Plus, which includes the base game, Enemy Within and other DLC packs,{{cite web|url=https://www.rpgsite.net/review/4773-xcom-enemy-unknown-plus-review|title=XCOM: Enemy Unknown Plus Review|first=Alex|last=Donaldson|work=RPGSite|date=March 29, 2016|accessdate=March 7, 2023}} was released for PlayStation Vita on March 22, 2016.{{cite web |url=https://www.videogamer.com/news/xcom-enemy-unknown-lands-on-ps-vita/ |title=XCOM: Enemy Unknown lands on PS Vita |first=David |last=Scammall |work=VideoGamer.com |date=March 22, 2016 |accessdate=November 18, 2023 |archive-date=March 18, 2018 |archive-url=https://web.archive.org/web/20180318054530/https://www.videogamer.com/news/xcom-enemy-unknown-lands-on-ps-vita |url-status=live}} Feral Interactive released the game for OS X and Linux in May 2013 and June 2014, respectively.{{cite magazine |url=https://www.gameinformer.com/b/news/archive/2013/05/06/xcom-enemy-unknown-available-for-mac-not-coming-to-steam.aspx |title=XCOM: Enemy Unknown Available For Mac, Not Planned For Steam |first=Mike |last=Futter |magazine=Game Informer |date=May 6, 2013 |access-date=November 18, 2023 |archive-date=April 25, 2023 |archive-url=https://web.archive.org/web/20230425043315/https://www.gameinformer.com/b/news/archive/2013/05/06/xcom-enemy-unknown-available-for-mac-not-coming-to-steam.aspx |url-status=live}}{{cite web |url=https://www.pcgamer.com/xcom-enemy-unknown-launches-for-linux-and-its-on-sale-too/ |title=XCOM: Enemy Unknown now available on Linux and SteamOS |first=Andy |last=Kelly |work=PC Gamer |date=June 20, 2014 |accessdate=November 18, 2023 |archive-date=November 26, 2022 |archive-url=https://web.archive.org/web/20221126151556/https://www.pcgamer.com/xcom-enemy-unknown-launches-for-linux-and-its-on-sale-too/ |url-status=live}}

Firaxis supported Enemy Unknown with post-launch content. The first downloadable content (DLC) pack, titled Slingshot, was released on November 4, 2012; it introduces several new council missions and a new playable character.{{cite magazine |url=https://www.gameinformer.com/b/news/archive/2012/12/04/xcom-enemy-unknown-39-s-slingshot-dlc-is-available-now.aspx |title=XCOM: Enemy Unknown's Slingshot DLC Is Available Now |first=Kyle |last=Hilliard |magazine=Game Informer |date=December 4, 2012 |access-date=November 18, 2023 |archive-date=January 26, 2021 |archive-url=https://web.archive.org/web/20210126125245/https://www.gameinformer.com/b/news/archive/2012/12/04/xcom-enemy-unknown-39-s-slingshot-dlc-is-available-now.aspx |url-status=live}} A free DLC titled Second Wave was released on January 4, 2013. It introduced adjustments to gameplay.{{cite web |url=https://www.ign.com/articles/2013/01/08/xcom-getting-second-wave-dlc-for-free |title=XCOM Getting 'Second Wave' DLC for Free |first=Anthony |last=Gallegos |work=IGN |date=January 8, 2013 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028180709/https://www.ign.com/articles/2013/01/08/xcom-getting-second-wave-dlc-for-free |url-status=live}} An expansion pack titled XCOM: Enemy Within, which was released worldwide on November 15, 2013.{{cite web |url=http://www.rockpapershotgun.com/2013/08/21/xcom-enemy-within-is-an-expansion-out-15th-november |title=XCOM: Enemy Within Is An Expansion, Out 15 November |website=Rock Paper Shotgun |date=August 21, 2013 |access-date=November 5, 2013 |last1=Walker |first1=John |archive-date=November 11, 2013 |archive-url=https://web.archive.org/web/20131111073448/http://www.rockpapershotgun.com/2013/08/21/xcom-enemy-within-is-an-expansion-out-15th-november/ |url-status=live }} retains the core storyline but adds a broad variety of content, including new weapons, special missions and the ability to enhance soldiers via genetic engineering and cybernetic implants. It also introduces forty new maps in the campaign mode and eight new multiplayer maps.{{cite web |url=https://www.ign.com/articles/2013/08/21/xcom-enemy-within-announced-tons-of-details |title=XCOM: Enemy Within Announced - Tons of Details! |first=Dan |last=Stepleton |work=IGN |date=August 21, 2013 |access-date=November 18, 2023 |archive-date=June 8, 2023 |archive-url=https://web.archive.org/web/20230608075345/https://www.ign.com/articles/2013/08/21/xcom-enemy-within-announced-tons-of-details |url-status=live}}{{cite web |url=https://arstechnica.com/gaming/2013/11/xcom-enemy-within-should-be-taken-with-a-heavy-dose-of-original-xcom/ |title=XCOM: Enemy Within should be taken with a heavy dose of original XCOM |first=Rowan |last=Kaiser |work=Ars Technica |date=December 11, 2023 |access-date=November 18, 2023 |archive-date=April 2, 2023 |archive-url=https://web.archive.org/web/20230402033343/https://arstechnica.com/gaming/2013/11/xcom-enemy-within-should-be-taken-with-a-heavy-dose-of-original-xcom/ |url-status=live}}

{{Video game reviews

| MC = PC: 89/100{{cite web |url=https://www.metacritic.com/game/xcom-enemy-unknown/critic-reviews/?platform=pc |title=XCOM: Enemy Unknown for PC Reviews |website=Metacritic |publisher=CBS Interactive |access-date=October 24, 2012 |archive-date=October 23, 2012 |archive-url=https://web.archive.org/web/20121023053832/http://www.metacritic.com/game/pc/xcom-enemy-unknown |url-status=live }}
PS3: 89/100{{cite web |url=https://www.metacritic.com/game/xcom-enemy-unknown/critic-reviews/?platform=playstation-3 |title=XCOM: Enemy Unknown for PlayStation 3 Reviews |website=Metacritic |publisher=CBS Interactive |access-date=October 24, 2012 |archive-date=October 27, 2012 |archive-url=https://web.archive.org/web/20121027034633/http://www.metacritic.com/game/playstation-3/xcom-enemy-unknown |url-status=live }}
X360: 90/100{{cite web |url=https://www.metacritic.com/game/xcom-enemy-unknown/critic-reviews/?platform=xbox-360 |title=XCOM: Enemy Unknown for Xbox 360 Reviews |website=Metacritic |publisher=CBS Interactive |access-date=October 24, 2012 |archive-date=November 13, 2012 |archive-url=https://web.archive.org/web/20121113135608/http://www.metacritic.com/game/xbox-360/xcom-enemy-unknown |url-status=live }}
iOS: 91/100{{cite web |url=https://www.metacritic.com/game/xcom-enemy-unknown/critic-reviews/?platform=ios-iphoneipad |title=XCOM: Enemy Unknown for iPhone/iPad Reviews |website=Metacritic |publisher=CBS Interactive |access-date=October 4, 2018 |archive-date=July 19, 2018 |archive-url=https://web.archive.org/web/20180719103209/http://www.metacritic.com/game/ios/xcom-enemy-unknown |url-status=live }}
VITA: 82/100{{cite web |url=https://www.metacritic.com/game/xcom-enemy-unknown/critic-reviews/?platform=playstation-vita |title=XCOM: Enemy Unknown Plus for PlayStation Vita Reviews |website=Metacritic |publisher=CBS Interactive |access-date=October 4, 2018 |archive-date=June 19, 2018 |archive-url=https://web.archive.org/web/20180619075125/http://www.metacritic.com/game/playstation-vita/xcom-enemy-unknown-plus |url-status=live }}

| Destruct = 9/10{{cite web |url=https://www.destructoid.com/reviews/review-xcom-enemy-unknown/ |title=Review: XCOM: Enemy Unknown |first=Allistair |last=Pinsof |work=Destructoid |date=October 8, 2012 |access-date=November 18, 2023 |archive-date=April 2, 2023 |archive-url=https://web.archive.org/web/20230402000115/https://www.destructoid.com/reviews/review-xcom-enemy-unknown/ |url-status=live}}

| EuroG = 9/10{{cite web |url=https://www.eurogamer.net/xcom-enemy-unknown-review-3 |title=XCOM: Enemy Unknown review |first=Rich |last=Stanton |work=Eurogamer |date=October 8, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028025543/https://www.eurogamer.net/xcom-enemy-unknown-review-3 |url-status=live}}

|PCGUS = 87/100{{cite web |url=https://www.pcgamer.com/xcom-enemy-unknown-review-2/ |title=XCOM: Enemy Unknown review |first=Evan |last=Lahti |work=PC Gamer |date=October 8, 2012 |access-date=November 18, 2023 |archive-date=July 24, 2023 |archive-url=https://web.archive.org/web/20230724162332/https://www.pcgamer.com/xcom-enemy-unknown-review-2/ |url-status=live}}

|IGN = 8.2/10{{cite web |url=https://www.ign.com/articles/2012/10/08/xcom-enemy-unknown-review |title=XCOM Enemy Unknown Review |first=Steve |last=Butts |work=IGN |date=October 9, 2012 |access-date=November 18, 2023 |archive-date=October 15, 2023 |archive-url=https://web.archive.org/web/20231015110407/https://www.ign.com/articles/2012/10/08/xcom-enemy-unknown-review |url-status=live}}

|GSpy = 5/5{{cite web |url=http://uk.pc.gamespy.com/pc/xcom-enemy-unknown/1226328p1.html |title=XCOM: Enemy Unknown Review |first=Dan |last=Stepleton |work=GameSpy |date=October 8, 2012 |access-date=November 18, 2023 |archive-date=March 4, 2016 |archive-url=https://web.archive.org/web/20160304054129/http://uk.pc.gamespy.com/pc/xcom-enemy-unknown/1226328p1.html |url-status=live}}

|GB = 5/5{{cite web |url=https://www.giantbomb.com/reviews/xcom-enemy-unknown-review/1900-533/ |title=XCOM: Enemy Unknown Review |first=Ryan |last=Davis |work=Giant Bomb |date=October 16, 2012 |access-date=November 18, 2023 |archive-date=June 25, 2023 |archive-url=https://web.archive.org/web/20230625200306/http://www.giantbomb.com/reviews/xcom-enemy-unknown-review/1900-533/ |url-status=live}}

|GSpot = 8.5/10{{cite web |url=https://www.gamespot.com/reviews/xcom-enemy-unknown-review/1900-6397898/ |title=XCOM: Enemy Unknown Review |first=Kevin |last=VanOrd |work=GameSpot |date=October 8, 2012 |access-date=November 18, 2023 |archive-date=May 18, 2022 |archive-url=https://web.archive.org/web/20220518075254/https://www.gamespot.com/reviews/xcom-enemy-unknown-review/1900-6397898/ |url-status=live}}

|GI = 9.5/10{{cite magazine |url=https://www.gameinformer.com/games/xcom_enemy_unknown/b/pc/archive/2012/10/05/review.aspx |title=XCOM: Enemy Unknown Review |first=Adam |last=Biessner |magazine=Game Informer |date=October 5, 2012 |access-date=November 18, 2023 |archive-date=March 31, 2023 |archive-url=https://web.archive.org/web/20230331181540/https://www.gameinformer.com/games/xcom_enemy_unknown/b/pc/archive/2012/10/05/review.aspx |url-status=live}}

|VB = 85/100{{cite web |url=https://venturebeat.com/2012/10/08/xcom-enemy-unknown-review |title=XCOM: Enemy Unknown is peerless in modern game design (review) |first=Rob |last=Savillo |work=VentureBeat |date=August 10, 2012 |access-date=November 18, 2023 |archive-date=January 21, 2022 |archive-url=https://web.archive.org/web/20220121054247/https://venturebeat.com/2012/10/08/xcom-enemy-unknown-review/ |url-status=live}}

|Poly = 8.5/10{{cite web |url=https://www.polygon.com/2013/1/24/3754534/xcom-enemy-unknown-review-blinded-by-science |title=XCOM: Enemy Unknown review: blinded by science |first=Russ |last=Pitts |work=Polygon |date=October 7, 2012 |access-date=November 18, 2023 |archive-date=February 25, 2023 |archive-url=https://web.archive.org/web/20230225212114/https://www.polygon.com/2013/1/24/3754534/xcom-enemy-unknown-review-blinded-by-science |url-status=live}}

}}

According to review aggregator Metacritic, XCOM: Enemy Unknown received "generally favourable reviews" from critics. Franchise creator Julian Gollop also praised the game, describing it as an "addictive and absorbing" experience; he liked the new alien design and enjoyed the challenging gameplay.{{cite web |url=https://www.eurogamer.net/x-communication-julian-gollop-and-jake-solomon-on-xcom |title=Two generations of XCOM: Gollop and Solomon on this year's remake |first=Owen |last=Faraday |work=Eurogamer |date=November 29, 2012 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028180710/https://www.eurogamer.net/x-communication-julian-gollop-and-jake-solomon-on-xcom |url-status=live}}

Evan Lahti from PC Gamer praised Firaxis for understanding the core gameplay pillars of the franchise and modernizing them for a new audience, resulting in a combat system that was "more coherent and elegant" than similar games in the same genre. He also liked the way the combat captured the "childlike joy" of moving a squad of action figures. Dan Stapleton from GameSpy described the game as "an amazingly addictive, challenging, and rewarding experience", praised its improvements over the gameplay of UFO: Enemy Unknown, and said its difficulty and randomness made it highly replayable. Kevin VanOrd from GameSpot wrote that the randomness of combat heightened the tension and anxiety, and the cinematic camera "[dramatized] the successes and failures". Steve Butts from IGN praised the environmental destructibility, which highlighted the "intensity of the battle" while providing new opportunities for players to plan their attacks. The lack of procedurally generated maps was criticized. Ryan Davis from Giant Bomb said the game was challenging but fair, and praised Firaxis for presenting the game's intricate mechanics in a way that was "digestible" for newcomers. Writing for Destructoid, Allistair Pinsof also praised the game's more-approachable nature. Multiplayer mode, however, was criticized for being too light on content.

Lahti was disappointed the base did not evolve despite the construction of new rooms, and that injured soldiers were never visualized in the base. He said these shortcomings can be easily overlooked because it was "a style of game that arguably hasn't existed" for nearly a decade. Stapleton liked the game for creating a sense of urgency because panic level will rise regardless of the player's actions, motivating players to perform well in ground combat missions. He also criticized base management for its "clumsy" user interface. Davis wrote he most enjoyed the "jigsaw nature of the administrative part", saying that resources being insufficient for pursuing all objectives forced players to compromise and prioritize certain research and construction projects. Pinsof also liked the looming threat of a game over scenario that resulted in a "relentlessly tense experience". Writing for Polygon, Russ Pitts wrote that the open-ended management options were at odds with the game's linear narrative structure, and that the turn-based combat outshone the game's strategic component.

Rob Savillo from VentureBeat wrote that players were frequently tasked with making choices whose outcomes were not immediately noticeable. Each soldier action and each strategic decision may result in unforeseen, irreversible consequences. He commended the Ironman mode for making all player decisions meaningful because they cannot reload a save. He praised the game for combining two distinct genres successfully, adding that it was "peerless in modern game design". VanOrd compared the premise to The War of the Worlds and noted the game never humanized its alien antagonists. Lahti and Pinsoff commented on the game's light narrative, but remarked that emergent gameplay created unique and personal stories for each player.{{cite web |url=https://www.pcgamer.com/the-strategy-game-of-the-year-2012-xcom-enemy-unknown/ |title=The Strategy Game of the Year 2012: XCOM: Enemy Unknown |first=Rich |last=McCormick |work=PC Gamer |date=December 31, 2012 |access-date=November 18, 2023 |archive-date=August 17, 2022 |archive-url=https://web.archive.org/web/20220817102232/https://www.pcgamer.com/the-strategy-game-of-the-year-2012-xcom-enemy-unknown/ |url-status=live}} Pinsof wrote the game sometimes punished players for failing but a small chance of victory always motivated them to continue playing. Arthur Gies from Polygon remarked that the losses in the game were "simultaneously heartbreaking and ruthlessly educational", as each failure prompted players to study the game's mechanics and refine their skills, thus encouraging them to replay the game repeatedly.{{cite web |url=https://www.polygon.com/2013/1/10/3860996/polygon-2012-games-of-the-year-5-xcom-enemy-unknown |title=Polygon 2012 Games of the Year #5: XCOM: Enemy Unknown |first=Arthur |last=Gies |work=Polygon |date=January 10, 2013 |access-date=November 18, 2023 |archive-date=October 28, 2023 |archive-url=https://web.archive.org/web/20231028103158/https://www.polygon.com/2013/1/10/3860996/polygon-2012-games-of-the-year-5-xcom-enemy-unknown |url-status=live}} Adam Biessener from Game Informer wrote that turn-based combat and real-time management presented "life-or-death conundrums to which there is no right answer", and concluded his review by writing XCOM: Enemy Unknown is a "singular achievement that every gamer deserves to experience".

The week of its release, XCOM: Enemy Unknown was the best selling game on Steam and the seventh best-selling at retail in the UK.{{cite web |url=https://www.pcgamesn.com/xcom-sales-flounder-consoles-win-pc |title=XCOM sales flounder on consoles, win on PC |first=Jeremy |last=Peel |work=PCGamesN |date=October 15, 2012 |access-date=November 18, 2023 |archive-date=September 26, 2023 |archive-url=https://web.archive.org/web/20230926162018/https://www.pcgamesn.com/xcom-sales-flounder-consoles-win-pc |url-status=live}} In the United States, it sold 114,000 copies and failed to enter the US monthly sales chart.{{cite web |url=https://www.engadget.com/2012-11-08-npd-dishonored-sold-460k-in-october-xcom-hit-114k.html |title=NPD: Dishonored sold 460K in October, XCOM hit 114K |first=David |last=Hinkle |work=Engadget |date=November 9, 2012 |access-date=November 18, 2023 |archive-date=November 18, 2023 |archive-url=https://web.archive.org/web/20231118170122/https://www.engadget.com/2012-11-08-npd-dishonored-sold-460k-in-october-xcom-hit-114k.html |url-status=live}} In February 2013, CEO of Take-Two Interactive Strauss Zelnick said the game was a commercial success for the company and had sold well digitally.{{cite web |url=https://venturebeat.com/games/xcom-enemy-unknown-leads-publisher-take-two-to-strong-fiscal-third-quarter/ |title=XCOM: Enemy Unknown leads publisher Take-Two to strong fiscal third quarter |first=Jeffery |last=Grubb |work=VentureBeat |date=February 5, 2013 |access-date=November 18, 2023 |archive-date=November 18, 2023 |archive-url=https://web.archive.org/web/20231118170124/https://venturebeat.com/games/xcom-enemy-unknown-leads-publisher-take-two-to-strong-fiscal-third-quarter/ |url-status=live}} According to Zelnick, the mobile version of the game was also a success, with the game being ranked as one of the highest-grossing release for iPad in its first week of release.{{cite web|url=https://www.gamesindustry.biz/xcom-proves-usd20-apps-can-work-says-take-two-ceo|title=XCOM proves $20 apps can work, says Take-Two CEO|first=Brendan|last=Sinclair|work=Gameindustry.biz|date=July 30, 2013|accessdate=February 12, 2024}}

GameSpy,{{cite web |url=http://pc.gamespy.com/articles/122/1227028p11.html |title=GameSpy's 2012 Game of The Year Awards |access-date=January 1, 2013 |archive-date=December 30, 2012 |archive-url=https://web.archive.org/web/20121230051341/http://pc.gamespy.com/articles/122/1227028p11.html |url-status=live}} Kotaku,{{cite web |url=http://kotaku.com/5973782/xcom-enemy-unknown-is-kotakus-2012-game-of-the-year |title=XCOM: Enemy Unknown is Kotaku's 2012 Game of the Year| first=Stephen|last= Totilo|date=January 7, 2013 |publisher=Kotaku.com |access-date=November 5, 2013 |archive-date=November 11, 2013 |archive-url=https://web.archive.org/web/20131111225656/http://kotaku.com/5973782/xcom-enemy-unknown-is-kotakus-2012-game-of-the-year |url-status=live }} MTV,{{cite web |url=http://multiplayerblog.mtv.com/2013/01/04/mtv-multiplayers-game-of-the-year-2012/ |title=MTV Multiplayer's Game of the Year 2012 |publisher=MTV |date=January 4, 2013 |access-date=November 5, 2013 |archive-date=November 12, 2013 |archive-url=https://web.archive.org/web/20131112194230/http://multiplayerblog.mtv.com/2013/01/04/mtv-multiplayers-game-of-the-year-2012/ |url-status=dead }} Giant Bomb,{{cite web |url=http://www.giantbomb.com/game-of-the-year-2012-day-five-recap/17-6906/ |title=Game of the Year 2012: Day Five Recap – Giant Bomb |publisher=Giantbomb.com |date=December 28, 2012 |access-date=November 5, 2013 |archive-date=January 27, 2013 |archive-url=https://web.archive.org/web/20130127091105/http://www.giantbomb.com/game-of-the-year-2012-day-five-recap/17-6906/ |url-status=live }} and GameTrailers{{cite web |url=http://www.gametrailers.com/full-episodes/pth9i9/gametrailers-game-of-the-year-awards-game-of-the-year |title=Game of the Year | GameTrailers Game of the Year Awards Full Episodes |publisher=GameTrailers |access-date=November 5, 2013 |archive-date=November 4, 2013 |archive-url=https://web.archive.org/web/20131104180028/http://www.gametrailers.com/full-episodes/pth9i9/gametrailers-game-of-the-year-awards-game-of-the-year |url-status=live }} selected XCOM: Enemy Unknown as their Game of the Year.

{{main|XCOM 2}}

The game, which was released when interest in turn-based strategy games was low, introduced the genre to a new generation of players.{{cite web |url=https://www.pcgamer.com/the-history-of-the-strategy-game/ |title=The history of the strategy game |first=Fraser |last=Brown |work=PC Gamer |date=December 24, 2018 |access-date=November 18, 2023 |archive-date=February 2, 2020 |archive-url=https://web.archive.org/web/20200202070046/https://www.pcgamer.com/the-history-of-the-strategy-game/ |url-status=live}}{{cite web |url=https://www.redbull.com/int-en/2016s-7-turn-based-strategy-games-you-need-to-play |title=The turn-based strategy game is back |first=Mike |last=Stubby |work=Red Bull |date=July 27, 2016 |access-date=November 18, 2023 |archive-date=August 13, 2023 |archive-url=https://web.archive.org/web/20230813105440/https://www.redbull.com/int-en/2016s-7-turn-based-strategy-games-you-need-to-play |url-status=live}} PC Gamer{{'}}s Fraser Brown, in a 2019 article, wrote that XCOM: Enemy Unknown "came along and lit a fire under the genre, arguably kicking off the decade of turn-based tactics games". The term "XCOM" became synonymous with the genre.{{cite web |url=https://www.pcgamer.com/turn-based-tactics-won-the-decade/ |title=Turn-based tactics won the decade |first=Fraser |last=Brown |work=PC Gamer |date=December 12, 2019 |access-date=November 18, 2023 |archive-date=September 13, 2023 |archive-url=https://web.archive.org/web/20230913040204/https://www.pcgamer.com/turn-based-tactics-won-the-decade/ |url-status=live}} In October 2022, Alex Donaldson from VG247 described the game as "the best franchise reboot of all time", praising Firaxis' ability to recapture the essence of the original game while modernizing it for a new generation of audience.{{cite web|url=https://www.vg247.com/a-decade-on-xcom-enemy-unknown-remains-the-best-franchise-reboot-of-all-time|title=A decade on, XCOM: Enemy Unknown remains the best franchise reboot of all time|first=Alex|last=Donaldson|work=VG 247|date=October 9, 2022|accessdate=March 9, 2023}}

Firaxis developed a sequel to XCOM: Enemy Unknown titled XCOM 2. The game takes place 20 years after the events of Enemy Unknown; its story is an alternative scenario in which XCOM failed to stop the alien invasion and humanity surrendered. The player controls a small resistance movement fighting the alien conquerors.{{cite web|url=http://uk.ign.com/articles/2015/06/01/xcom-2-announced-ign-first|title=XCOM 2 Announced -- IGN First|first=Dan|last=Stapleton|work=IGN|date=June 1, 2015|access-date=June 1, 2015|archive-date=August 1, 2016|archive-url=https://web.archive.org/web/20160801185807/http://uk.ign.com/articles/2015/06/01/xcom-2-announced-ign-first|url-status=live}} XCOM 2 was released for Windows in February 2016 and for consoles in September the same year.{{cite web|url=https://www.eurogamer.net/xcom-2-delayed-three-weeks-on-console|title=XCOM 2 delayed three weeks on console|first=Jeffery|last=Matulef|work=Eurogamer|date=August 4, 2016|accessdate=March 7, 2024}} A spin-off game, XCOM: Chimera Squad, was released in April 2020.{{cite web|url=https://www.gamespot.com/articles/xcom-spin-off-chimera-squad-announced-and-its-comi/1100-6475944/|title=XCOM Spin-Off Chimera Squad Announced, And It's Coming Very Soon|first=Steve|last=Watts|work=GameSpot|date=April 14, 2020|accessdate=March 9, 2024}} A board game based on Enemy Unknown, developed and published by Fantasy Flight Games, was released on January 28, 2015.{{cite magazine|url=https://www.gameinformer.com/b/news/archive/2015/01/16/pre-load-the-xcom-board-game-app-now-before-the-game-arrives-this-month.aspx|archive-url=https://web.archive.org/web/20150119232548/http://www.gameinformer.com/b/news/archive/2015/01/16/pre-load-the-xcom-board-game-app-now-before-the-game-arrives-this-month.aspx|url-status=live|archive-date=January 19, 2015|title=Pre-Load The XCOM Board Game App Now Before The Game Arrives This Month|first=Mike|last=Futter|magazine=Game Informer|date=January 16, 2015|access-date=March 9, 2024}}

In early 2013, a partial conversion mod for the game was released. Titled Long War, the mod introduced changes to many of the game's existing features, added new concepts, and brought back more concepts from the original game.{{cite web|url=https://www.rockpapershotgun.com/xcom-hardcore-mod|title=Terror From The Details: XCOM's Amazing Long War Mod|first=Alec|last=Meer|work=Rock, Paper, Shotgun|date=May 16, 2014|accessdate=March 9, 2024}} The mod was praised by players and members of the Firaxis development team, and 2K recruited the team to create several day-one mods for XCOM 2.{{cite web|url=https://www.pcgamer.com/how-one-xcom-mod-spawned-a-development-studio/|title=How one XCOM mod spawned a development studio|first=Joe|last=Donnelly|work=PC Gamer|date=July 29, 2016|accessdate=March 9, 2024}}

{{Reflist}}

• {{Official website|https://www.xcom.com/xcom-enemy-unknown}}

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