Halo: Combat Evolved

Halo: Combat Evolved is a 2001 first-person shooter game developed by Bungie and published by Microsoft Game Studios, the first installment in the Halo franchise, released for the Xbox on November 15, 2001, with ports to Microsoft Windows and Mac OS X following in 2003. Set in the 26th century, players assume the role of Master Chief, a cybernetically enhanced supersoldier accompanied by an artificial intelligence construct named Cortana and the human forces of the United Nations Space Command, battling an alien theocracy known as the Covenant while uncovering the secrets of the eponymous Halo, a ring-shaped artificial world.