The Top 7... alien invasions

2. X-COM: UFO Defense (1993, PC)

It's all-out war. Most games pit you as one character versus an overwhelming force, but this classic strategy gem brings the totality of global alien invasion into your crosshairs. You're charged with discovering and destroying many species of aliens while keeping a close eye on the progress of the invasion - over the entire world.

With combat that requires a serious mix of brain and firepower, the game quickly picked up legions of fans. Think about it: the entire world is crawling with aliens intent to wipe out the human race. Enter: you. It's a thrilling battle fought on a massive scale.