UFO: Enemy Unknown (1994-)

UFO: Enemy Unknown (original title), also known as X-COM: UFO Defense in North America, is a 1994 science fiction strategy video game developed by Mythos Games and MicroProse. It was published by MicroProse for DOS and Amiga computers, the Amiga CD32 console, and the PlayStation. Originally planned by Julian Gollop as a sequel to Mythos Games' 1988 Laser Squad, the game mixes real-time management simulation with turn-based tactics. The player takes the role of commander of X-COM – an international paramilitary and scientific organisation secretly defending Earth from an alien invasion. Through the game, the player is tasked with issuing orders to individual X-COM troops in a series of turn-based tactical missions. At strategic scale, the player directs the research and development of new technologies, builds and expands X-COM's bases, manages the organisation's finances and personnel, and monitors and responds to UFO activity.

Despite its troubled development, including having been almost cancelled twice, the game received strong reviews and was commercially successful, turning into a runaway sleeper hit and acquiring a cult following among strategy fans; several publications have listed Enemy Unknown as one of the best video games ever made, including IGN ranking it as the best PC game of all time in 2007. It was the first and best-received entry in the X-COM series and has directly inspired several similar games. An official remake of the game, XCOM: Enemy Unknown, was published in 2012.

Images from MobyGames