Based on Games Workshop's Warhammer 40,000 universe, Space Marine is a third-person shooter that pits elite human soldiers against two deadly factions: the feral Orks and the shadowy Chaos. You take command of Captain Titus of the Ultramarines, who must defend a strategically critical weapons-producing planet from falling into enemy hands. Both shooting and melee combat are supported, with players able to seamlessly switch between fighting styles simply by tapping a button. Defeating enemies will earn your character "fury," which can be used to trigger more powerful ranged or melee attacks. In addition to the single-player campaign, Space Marine includes co-op play as well as competitive multiplayer game types.