Combat missions

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.^[1]

Most missions in the campaign occur on maps randomly selected from a handcrafted set; enemies are then randomly placed on these maps.^[2] 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.^[3] Most missions require players to eliminate all threats in a map, though players can choose to retreat and abandon the mission if the situation goes awry.^[4][5] The game has four difficulty levels: easy, normal, classic and impossible.^[6] There is also an "ironman mode", which limits the player to one save.^[7]

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.^[4] The game's user interface informs the player of the possibility of landing a successful shot and the amount of damage they will deal.^[8] 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.^[9]

As soldiers progress through the game, they earn experience and are promoted, allowing players to specialize them.^[4] As soldiers earn promotions, for each rank they gain, players can select one out of two perks.^[10] 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 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.^[11][12] 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.^[12] A class cannot be changed once it has been selected.^[11] Each recruit's name and appearance can be customized.^[13] Soldiers may permanently die once their health reaches zero if they are not saved in time.^[4] Soldiers can experience panic during a mission, which can make the player lose control of that character for a turn.^[7]

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.^[14]

Base management

XCOM's underground headquarters is presented in a view dubbed the "ant farm".^[15] 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.^[16] 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.^[17] It is also where recruits in the game rest, exercise and tend to their wounds.^[18] A memorial wall to soldiers killed in action is also visible.^[19] 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.^[16] The game will end If eight out of the sixteen Council nations decide to leave.^[9] 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.^[20][16]

Setting

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.

Story

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 and using the psychic gift to control the ship and fly it further from Earth, causing the ship to self-destruct.

Project origin

Being a fan of X-COM: UFO Defense (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.^[25] 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.^[26] 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.^[25]

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.^[25] 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.^[27]

Gameplay design

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.^[28] 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.^[26] 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.^[28] 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.^[28][29][30] 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.^[31] According to DeAngelis, each combat mission should last around 20 minutes and more-lengthy missions should not exceed 50 minutes.^[29] According to Sid Meier, the game was designed to cater for fans of action games, real-time strategy games and role-playing video games.^[32]

The team deemed "permanent death, destruction and turn-based combat" the franchise's major pillars. The game was intended to be challenging,^[33] 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.^[29] The team also wanted the game to be fair so, unlike the original game, aliens will not attack the player until they are revealed.^[34] 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.^[29] Producer Garth DeAngelis further added that through these losses, the team created a "sense of fear reverberating through the entire experience".^[35] 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.^[36] 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.^[37]

The game's strategic layer also went through multiple changes and was redesigned two years into the game's development.^[31] 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.^[25] 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.^[38]

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.^[27] 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.^[39]

Art and music

The developers, who were inspired by animals such as insects, spider monkeys and gorillas, wanted to modernize designs for some of the aliens from X-COM: UFO Defense.^[40] 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 X-COM: UFO Defense. The Mutons were designed to be physically imposing and ape-like;^[41] the Chryssalids are now an alien quadruped with no humanoid characteristics;^[31] 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.^[41] Other alien designs in the game were inspired by Men in Black and The X-Files.^[42]

Plans to include large-scale aliens were scrapped. The Sectapods 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.^[40] The design of XCOM's soldiers was inspired by action figures; the team strove for a stylized, bright, flat-textured look.^[43][44] 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.^[45]

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 X-COM: UFO Defense to better understand the music.^[46] 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.^[36]

Critical reception

According to review aggregator Metacritic, XCOM: Enemy Unknown received "generally favourable reviews" from critics.^[68] 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.^[81]

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.^[78] Dan Stapleton from GameSpy described the game as "an amazingly addictive, challenging, and rewarding experience", praised its improvements over the gameplay of UFO: Enemy Defense, and said its difficulty and randomness made it highly replayable.^[75] Kevin VanOrd from GameSpot wrote that the randomness of combat heightened the tension and anxiety, and the cinematic camera "[dramatized] the successes and failures".^[74] 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.^[77] The lack of procedurally generated maps was criticized.^[74][75] 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.^[76] Writing for Destructoid, Allistair Pinsof also praised the game's more-approachable nature.^[1] Multiplayer mode, however, was criticized for being too light on content.^[7][78]

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.^[78] 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.^[75] 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.^[76] Pinsof also liked the looming threat of a game over scenario that resulted in a "relentlessly tense experience".^[1] 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.^[79]

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 thy cannot reload a save.^[80] He praised the game for combining two distinct genres successfully, adding that it was "peerless in modern game design".^[80] VanOrd compared the premise to The War of the Worlds and noted the game never humanized its alien antagonists.^[74] Lahti and Pinsoff commented on the game's light narrative, but remarked that emergent gameplay created unique and personal stories for each player.^[1][78][82] Pinsof wrote the game sometimes punished players for failing but a small chance of victory always motivated them to continue playing.^[1] 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.^[83] 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".^[73]

Sales

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.^[84] In the United States, it sold 114,000 copies and failed to enter the US monthly sales chart.^[85] 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.^[86] 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.^[87]

Accolades

GameSpy,^[88] Kotaku,^[89] MTV,^[90] Giant Bomb,^[91] and GameTrailers^[92] selected XCOM: Enemy Unknown as their Game of the Year.