As a single-player or multiplayer FPS experience Perfect Dark is unparalleled on the console systems.
Halo: Combat Evolved
Not only is this easily the best of the Xbox launch games, but it's easily one of the best shooters ever, on any platform.
It's not just one of the single most atmospheric games ever created, but it's also quite simply one of the best.
Gone Home is a first-person game entirely about exploration, mystery, and discovery.
Unreal Tournament (1999)
Unreal Tournament is the most complete first-person shooter available.
Crysis is a Sci-Fi FPS game for the PC in which mankind must struggle to survive in the face of an alien invasion.
Command & Conquer: Red Alert
There are new weapons, enemies, and levels, but the game engine and basic play are essentially the same.
A prequel to the original Halo, Halo: Reach follows a SPARTAN squad as they fight the Covenant on a besieged fortress world.
Bungie's popular first-person shooter makes its debut on the Xbox 360 with Halo 3.