UFO: Alien Invasion is described as 'strategy video game in which the player fights aliens that are trying to take control of the Earth. The game is heavily influenced by the X-COM series (mostly by UFO: Enemy Unknown)'. There are 2 games similar to UFO: Alien Invasion for GOG.com, Linux, Mac, Steam and Windows. The best alternative is Xenonauts.
1 October, 1979: Unidentified forces presumed of extraterrestrial origin arrive in Earth orbit. Panic spreads across the globe as attempts at communication fail and attempts to engage the invaders are met with heavy losses and little success. Represent entire series of Xenonauts games including Xenonauts, Xenonauts-2.