The original concept for X-COM, as a counter-alien invasion task force, was developed in the early 1990s leading up to the 1994 release of the first game.
The original X-COM game, also known as UFO Defense, was released, introducing players to the alien invasion theme and turn-based tactics.
Firaxis Games started developing the reboot of the classic X-COM series, titled XCOM: Enemy Unknown, aiming to modernize the strategy experience.
Firaxis Games officially announced the development of XCOM: Enemy Unknown, the first new entry in the series in over a decade.
XCOM: Enemy Unknown was released worldwide to critical acclaim, revitalizing the tactical strategy franchise with modern graphics and gameplay.
Firaxis released the Enemy Within expansion pack for XCOM: Enemy Unknown, adding new missions, enemies, and gameplay mechanics.
Multiple UFO sightings are recorded around the globe, marking the initial awareness of the alien presence on Earth.
International governments agree to establish a secret paramilitary organization known as XCOM to combat the extraterrestrial threat.
XCOM personnel encounter hostile alien forces directly for the first time during a crash site recovery mission.
XCOM establishes a mobile underground base equipped with research, engineering, and command capabilities.
Recovered alien technology is studied, enabling advancements in human weaponry and equipment.
XCOM conducts various missions worldwide to repel alien incursions and recover vital technology and information.
Research breakthroughs allow for the production of plasma weapons and advanced armor for XCOM operatives.
XCOM launches an assault on a major alien base, significantly disrupting the alien operations on Earth.
XCOM faces off against the alien leaders known as Ethereals to end the invasion threat once and for all.
