Ufo: Enemy Unknown -

The story continues in X-COM: Terror from the Deep , where a second wave of aliens awakens from the ocean floor.

You recover alien corpses and technology from crash sites to develop laser and plasma weaponry. UFO: Enemy Unknown

The ultimate goal is to destroy the Alien Brain , a massive bio-computer that serves as the mastermind and central hub for the invasion. The Endings The story continues in X-COM: Terror from the

The modern XCOM: Enemy Unknown reboots this story for a new timeline. In the timeline of XCOM 2 , it is revealed that X-COM actually lost the war early on, and the "victory" from the previous game was a simulation run in the Commander's mind while they were held captive. The Endings The modern XCOM: Enemy Unknown reboots

As the Commander, you start with basic human ballistics while fighting various alien species, such as the physically frail but psionic and the brutish Mutons . The "story" is largely driven by your research:

You discover that alien technology relies on Elerium-115 , a stable heavy element not found on Earth, which becomes the most vital resource for humanity's advanced crafts and weapons.