Ten great games about alien invasion

Valve's brilliant shooter dumps scientist Gordon Freeman on a dystopian Earth crushed by the evil Combine alien invasion force. The visuals are wonderful, the physics are astonishing and the Orwellian setting of City 17 provides a nightmarish backdrop to the tense story of rebellion, sacrifice and shooting stuff. Set in an alternate post-second world war period in which an alien race known as the Chimera has infected and enslaved most of humanity, Insomniac's shooter series has the gritty muted look of a 1950s British sci-fi movie, and is notable in that it starts not in New York or London but in … Grimsby, a town criminally overlooked by mainstream action adventure games. The legendary X-COM series of strategy games has players controlling small squads of soldiers touching down at alien invasion sites to destroy the monsters and gather their artefacts for research. Combining tense tactical fights with resource management, the game was utterly gripping, and the reboot series has revived the turn-based combat genre for a whole new generation.