This is the stand alone game Code Red: Alien Arena v4, based off the Quake II engine. This full game includes 18 maps to choose from, including 4 Capture the Flag, 2 All Out Assault, and 3 1v1 Tournament levels spanning online deathmatch, CTF, and team deathmatch. Version 4 introduces the new assault mode, which includes driveable vehicles.
http://www.gamespot.com/pc/action/qu...c&subj=6126974