XCOM

XCOM is a science fiction video game franchise featuring an elite international organization tasked with countering alien invasions of Earth. The series began with the strategy video game UFO: Enemy Unknown created by Julian Gollop's Mythos Games and MicroProse in 1994. The original lineup by MicroProse included six published and at least two canceled games, as well as two novels. The X-COM series, in particular its original entry, achieved a sizable cult following and has influenced many other video games; including the creation of a number of clones, spiritual successors, and unofficial remakes.
A reboot series was published by 2K Games, beginning with the strategy video game XCOM: Enemy Unknown, developed by Firaxis Games and released in 2012 to critical and commercial success. It was followed by the prequel The Bureau: XCOM Declassified and the sequels XCOM 2 and XCOM: Chimera Squad.

Games

Released

X-COM series
XCOM reboot series

Title	Release	Developer	Publisher
UFO: Enemy Unknown		Mythos Games MicroProse	MicroProse
X-COM: Terror from the Deep		MicroProse	MicroProse
X-COM: Apocalypse		Mythos Games MicroProse	MicroProse
X-COM: Interceptor		MicroProse	MicroProse
X-COM: First Alien Invasion		Hasbro Interactive	Hasbro
X-COM: Enforcer		Hasbro Interactive	Infogrames
XCOM: Enemy Unknown		Firaxis Games	2K Games
The Bureau: XCOM Declassified		Irrational Games 2K Australia 2K Marin	2K Games
XCOM: Enemy Within		Firaxis Games	2K Games
XCOM 2		Firaxis Games	2K Games
XCOM 2: War of the Chosen		Firaxis Games	2K Games
XCOM: Chimera Squad		Firaxis Games	2K Games
XCOM: Legends		Iridium Starfish	2K Games

Cancelled

Original ''X-COM'' series (1994–2001)

The X-COM core series consisted of four main games published by MicroProse: UFO: Enemy Unknown, X-COM: Terror from the Deep, X-COM: Apocalypse and X-COM: Interceptor. The premise of the franchise is that an alien invasion beginning in 1999 prompts the creation of a clandestine paramilitary organization codenamed X-COM by a coalition of funding nations. The player is charged with leading this force and tasked to secretly engage and research the alien threat. The sequels, against new alien invasions, are set underwater, in a futuristic megacity, and in space.
UFO: Enemy Unknown, featuring a turn-based ground combat system, remains the most popular and successful game in the series, having been often featured on various lists of best video games of all time. The first sequel, Terror from the Deep, was quickly created by MicroProse's internal team; based on the same game engine and used largely identical gameplay mechanics. Apocalypse took several new directions with the series, introducing an optional real-time combat system and shifting the aesthetics to a retro-futuristic style. A spin-off game, Interceptor, constitutes a hybrid of a strategy game and a space combat flight simulator.
After Interceptor, Hasbro Interactive purchased MicroProse, acquiring its studios and the X-COM brand. There were talks of X-COM toys, comics, and even a cartoon show. A budget range, turn-based tactical play-by-mail multiplayer game Em@il Games: X-COM was released in 1999. In 2001, Hasbro published X-COM: Enforcer, a poorly received third-person shooter loosely based on the events of Enemy Unknown, marking a low point in the series. The X-COM games were also released as part of four compilation releases: X-COM , X-COM Collection and X-COM: Complete Pack, as well as in 2K Huge Games Pack in 2009.
At least two more major titles have been planned for this series. One of them was X-COM: Genesis, a real-time strategy and tactics game "going back to the roots but in full 3D." Another was X-COM: Alliance, an Aliens-inspired mix of strategy game and first-person perspective tactical shooter, using the licensed original Unreal Engine. However, both of these projects were cancelled after ex-MicroProse Hasbro Interactive studios were all shut down in 1999–2000. Terry Greer, a former senior artist and head of game design at MicroProse UK, disclosed: "We'd also discussed other avenues for future games including time travel, retaking the solar system, and resistance movement concept where you had to fight back after the world was taken and humanity was totally under the alien yoke."
OpenXcom is an open source re-implementation of the first game in the series intended to fix all the bugs and enable modding. OpenApoc is a similar open source project for X-COM: Apocalypse.

''XCOM'' series (2012–present)

In 2010, 2K Marin announced they were working on re-imagining of X-COM, relabeled as XCOM. It was described as a tactical and strategic first-person shooter that would combine elements from the original X-COM alongside a new setting and viewpoint while keeping some main concepts from the original game series. The setting received a complete overhaul, now based in the early 1960s, with the original XCOM organization being a secret U.S. federal agency. Originally planned for 2011, the game was repeatedly redesigned by different studios before being finally released in 2013 as The Bureau: XCOM Declassified for Windows, OS X, PlayStation 3 and Xbox 360.
In 2012, Firaxis Games announced the development of a Windows, PlayStation 3 and Xbox 360 strategy game XCOM: Enemy Unknown, a "re-imagination" of UFO: Enemy Unknown with real-time strategic view, turn-based combat and destructible tactical environments more in the vein of the original X-COM game and set in a more contemporary setting than the XCOM game by 2K Marin. XCOM: Enemy Unknown was released later that same year to critical acclaim, winning multiple "Game of the Year" awards. X-COM creator Julian Gollop hailed it as "a phoenix rising from the ashes of the X-COM disaster," saying that "it’s amazing that after 20 years, a brand that had gone so badly in the wrong direction has finally been put right." It was also ported to Android, iOS, OS X, Linux, and PlayStation Vita. In 2013, Firaxis released a downloadable content for the base game XCOM: Enemy Unknown titled XCOM: Enemy Within. It was made available for PC, as well as for iOS, the PlayStation 3 and Xbox 360.
In 2015, Firaxis announced a sequel, XCOM 2. It was released in 2016 for Windows, PlayStation 4, Xbox One, OS X, and Linux. Its expansion, XCOM 2: War of the Chosen, followed in 2017. The game is set in an alternate reality after the events of X-COM: Enemy Unknown in which the aliens won the war and rule Earth and X-COM tries to overthrow them.
The next game in the series, XCOM: Chimera Squad, was released in April 2020, for Windows. Unlike the global scale of previous games, Chimera Squad focused on a specific city, giving the player control of a diverse squad of humans and aliens. The game introduced several changes to game mechanics, such as replacing randomly generated and customizable squad members with preset and unique soldiers, and utilizing "interleaved turns" instead of a team-by-team turn system.

Julian Gollop's unofficial games

The Dreamland Chronicles: Freedom Ridge was a game for the PC and PlayStation 2 by Julian Gollop's Mythos Games, claimed to having been "essentially a remake of the first X-Com with 3D graphics." The Dreamland Chronicles was canceled in 2001 and Mythos Games soon ceased to exist.
Laser Squad Nemesis is a 2002 low-budget PC turn-based tactics game developed by Gollop's next company Codo Technologies and very similar to the turn-based Battlescape combat system of the first X-COM. In 2005, Codo Technologies and publisher Namco also released Rebelstar: Tactical Command, a Game Boy Advance turn-based tactical role-playing game that too was reminiscent of the early Battlescape system.
Phoenix Point is a strategy and turn-based tactics video game for Windows, and OS X that has the open world, strategic layers of the X-COM style games of the 1990s like Enemy Unknown and Apocalypse together with the presentation and tactical mechanics of the more recent Firaxis reboot games. The game was developed by Gollop with Snapshot Games, an independent game studio in Bulgaria. Phoenix Point, described as a spiritual successor to X-COM, was released in December 2019.

Other media

Literature

Two X-COM novels have been published based on the first game in the series: Diane Duane's X-COM: UFO Defense - A Novel and Vladimir Vasilyev's Enemy Unknown. The reboot series' novel is titled XCOM 2: Resurrection by Greg Keyes and was published in 2015, bridging the plots of XCOM and its sequel. In 2017, a second novel was published with the title XCOM 2: Escalation by Rick Barba.
MicroProse's manual/documentation writer John Possidente also wrote three short stories, "Decommissioning", "Manley's Deposition", and "Moray in the Wreck", taking place between the events of the first two games in the series. More recently, X-COM co-designer Dave Ellis and artist Jon McCoy released a free online tribute digital comic titled Deep Rising, with music created by X-COM composer John Broomhall.