co-op multiplayer games for the xbox360

Game *	Players	Score	Genre	Release Date	Notes
1XR	6	xx	Racing, Driving, Action	October 1, 2006	search terms
Ace Combat 6: Fires of Liberation	Multi	80	Flight Combat	October 1, 2007	search terms
Aegis Wing	4	58	Shooter, Action	May 16, 2007	search terms
Alien Hominid HD	4	79	Third-Person Shooter	March 1, 2007	search terms
Arkadian Warriors	2	60	Action	December 12, 2007	search terms
Army of Two	2	xx	Action, First-Person Shooter	June 1, 2007	search terms
Assault Heroes	2	79	Action, Adventure, Shoot 'em Up	December 13, 2006	search terms
Blazing Angels 2: Secret Missions	16	72	Flight Combat Simulation, Action, Shooter	September 18, 2007	search terms
Blazing Angels: Secret Missions	16		Flight Combat Simulation, Action, Shooter	March 27, 2007	search terms
Blazing Angels: Squadrons of WWII	16	66	Flight Combat Simulation, Action, Shooter	March 23, 2006	search terms
Boogie Bunnies	2	55	Puzzle	January 16, 2008	search terms
Borderlands	4	xx	First-Person Shooter, Action, Role-Playing Game	October 1, 2008	search terms
Call of Duty 2	16	89	First-Person Shooter, Action	November 15, 2005	search terms
Chromehounds	12	71	Action, Third-Person Shooter	July 11, 2006	search terms
Cloning Clyde	8	81	Action	July 19, 2006	search terms
Conflict: Denied Ops	2	50	First-Person Shooter, Action	April 1, 2008	search terms
Crackdown	2	83	Action, Driving	February 1, 2007	search terms
Crash of the Titans	2	65	Action, Adventure	October 2, 2007	search terms
Crossfire	2		First-Person Shooter, Action	June 1, 2007	search terms
Defender	2	58	Action, Shooter	November 15, 2006	search terms
Doom	4	80	First-Person Shooter, Action	September 27, 2006	search terms
Double Dragon	2	57	Action, Beat-'Em-Up	March 1, 2007	search terms
Dynasty Warriors 5: Empires	2	61	Action	March 28, 2006	search terms
Earth Defense Force 2017	2	69	Third-Person Shooter	March 1, 2007	search terms
Eragon	2	48	Action, Adventure	November 14, 2006	search terms
Fantastic Four: Rise of the Silver Surfer	4	45	Third-Person Action, Adventure	June 15, 2007	search terms
Frogger	2	62	Action	September 1, 2006	search terms
Golden Axe (XBLA)	2	68	Action, Beat-'Em-Up	July 11, 2007	search terms
Guitar Hero II	2	92	Music	February 1, 2007	search terms
Gyruss	2	56	Shooter	April 18, 2007	search terms
Haze	Multi		First-Person Shooter	February 1, 2007	search terms
Heavy Weapon: Atomic Tank	4	77	Shooter, Action	January 17, 2007	search terms
Hellboy	4	xx	Action, Beat-'Em-Up	June 1, 2007	search terms
Joust	2	68	Action, Platform	November 22, 2005	search terms
Kane & Lynch: Dead Men	2	66	Action	April 1, 2007	search terms
Kingdom Under Fire: Circle of Doom	4	55	Action, Role-Playing Game	October 1, 2006	search terms
Left 4 Dead	8	xx	First-Person Shooter, Action	October 1, 2007	search terms
Looney Tunes: Acme Arsenal	2	40	Action, Adventure	November 1, 2007	search terms
Marvel: Ultimate Alliance	4	82	Action, Role-Playing Game	November 1, 2006	search terms
Mercenaries 2: World in Flames	2	xx	Action, Adventure, Third-Person Shooter	November 1, 2007	search terms
Metal Slug 3	2	79	Action	January 2, 2008	search terms
Mutant Storm Reloaded	2	77	Shooter	November 22, 2005	search terms
N+	4	xx	Action	April 1, 2008	search terms
NBA 2K8	2	81	Sports, Basketball	October 1, 2007	search terms
Omega Five	2	72	Action, Shoot-'em-up	January 1, 2008	search terms
Outfit, The	8	70	Third-Person Action	March 13, 2006	search terms
Paperboy	2	71	Action	February 14, 2007	search terms
Perfect Dark Zero	32	81	First-Person Shooter, Action	November 16, 2005	search terms
Robotron: 2084	2	65	Shooter	January 6, 2006	search terms
Rocketmen: Axis of Evil	4	xx	Shooter	November 1, 2007	search terms
Root Beer Tapper	2	61	Action	February 7, 2007	search terms
Rush'n Attack	2	58	Action, Platform	May 23, 2007	search terms
Saints Row 2	2	xx	Action, Adventure	October 1, 2008	search terms
Samurai Warriors 2	4	52	Third-Person Action, Beat-'Em-Up	September 19, 2006	search terms
Samurai Warriors 2 Empires	4	53	Third-Person Action, Beat-'Em-Up, Strategy	February 27, 2007	search terms
Shrek-N-Roll	2	48	Puzzle	November 14, 2007	search terms
Soltrio Solitaire	2	59	Card Games	May 16, 2007	search terms
Spider-Man: Friend or Foe	2	60	Action	November 1, 2007	search terms
Streets of Rage 2	2	75	Action, Beat-'Em-Up	August 29, 2007	search terms
Super Contra	2	60	Action, Shooter	July 25, 2007	search terms
Teenage Mutant Ninja Turtles	4	66	Action, Beat-'Em-Up	March 14, 2007	confirmed
Tom Clancy's Ghost Recon Advanced Warfighter	16	90	First-Person Shooter, Action	March 7, 2006	search terms
Undertow	16	76	Action, Shooter	September 1, 2007	search terms
63 games

This site is built by a ugly perl script that crawls metacritic. I'm not affiliated with them in any way. I just find their layout to be clean and easy to parse, and their game database seems to be very complete. Someday, I hope to discontinue this service when a major game site treats co-op multiplayer as a searchable game feature!