Halo: Combat Evolved and Halo 2 for XBOX .

Halo: Combat Evolved
You are the ultimate commando - a cybernetically enhanced soldier representing the peak of human military evolution. You are efficient, skilled, and dangerous. A sci-fi shooter that takes place on a mysterious alien ring-world, Halo will have you battling through amazing indoor and outdoor environments, in vehicles, and on foot with the largest arsenal of futuristic weapons, vehicles, and combat roles of any shooter ever.

Features:

• Action-shooter game with vehicular combat elements
• You play as a trooper thrust into a hostile alien world
• Deploy a variety of enemy flyers and on-ground buggies
• Battle it out in split-screen deathmatch mode
• For 1 to 4 players, also supports LAN play

Halo 2
Halo 2 returns you to the role of the Master Chief - still humanity's best weapon against the Covenant. Their defeat at Halo was only temporary, and they are pursuing their goal - the complete obliteration of humankind - with renewed zeal. Human military forces are exhausted and unable to stave off the Covenant's rapid advance toward Earth.

Features:

• Covenant forces attack Earth, another Halo ring comes into play, and the Master Chief takes the battle to the Covenant
• New vehicles and weapons, destructible environments, low gravity, online play, Human vs. Covenant multiplayer battles, improved AI, and more
• Better control: sprint at twice normal speed, peek around corners, chain melee attacks into devastating combos
• Completely rewritten graphics engine allows previously unimaginable complexity and detail
• Multiplayer modes include Oddball, Race, Slayer, Capture the Flag, and exclusive modes only available for play over Xbox Live