Halo 1

Halo: Combat Evolved is a 2001 first-person shooter video game developed by Bungie and published by Microsoft Game Studios for the Xbox. The game was ported to Microsoft Windows and Mac OS X in 2003. It was later released as a downloadable Xbox Original for the Xbox 360. Halo is set in the 26th century, with the player assuming the role of Master Chief, a cybernetically enhanced supersoldier. Master Chief is accompanied by Cortana, an artificial intelligence. Players battle aliens as they attempt to uncover the secrets of the eponymous Halo, a ring-shaped artificial world.