UFO: Alien Invasion is an entirely free and open-source game inspired by the X-COM video game series. The year is 2084, and you control a secret organization tasked with defending Earth from an alien invasion.
aliens freeware science fiction strategy turn-based strategyX-COM: UFO Defense (UFO: Enemy Unknown in Europe) is a science fiction strategy game developed by Mythos Games. It was published by MicroProse Software (Geoff Crammond’s former company) and released for Amiga and DOS in 1994.
aga aliens rpg elements science fiction squad management strategy tactical-rpg turn-based strategy