XCOM: Enemy Unknown is a turn-based tactical role-playing video game developed by Firaxis Games for publisher 2K Games. The game is a "reimagined" remake of the 1994 cult classic strategy game UFO: Enemy Unknown (also known as X-COM: UFO Defense).
Set in the near future during an alien invasion of Earth, XCOM: Enemy Unknown puts the player in control of an elite multinational paramilitary organization called XCOM and tasked with defending the Earth. The player commands troops in the field in a series of turn-based tactical missions; between missions, the player directs the research and development of new technologies from recovered alien technology and captured prisoners, expands XCOM's base of operations, manages XCOM's finances, and monitors and responds to alien activity.
The game is set in the near future, 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 XCOM (short for Extraterrestrial Combat Unit), the most elite military and scientific organization in human history, tasked with defending them from the alien attack. The player assumes the role of the commander of XCOM, and proceeds to engage in a war against an extraterrestrial enemy with overwhelming technological superiority.