Best Co-Op retro games?

[MattJay]

As I discovered today thanks to Noiseredux, A Nightmare on Elm Street (NES).

Also Goof Troop on SNES is basically a co-op Zelda.

[wip3outguy7]

Genesis:
Gunstar Heroes
Rolling Thunder 2
Streets of Rage 2
Two Crude Dudes

SNES:
Brawl Brothers

Dreamcast:
+1 for Cannon Spike
Zombie Revenge

PS1:
Loaded (also available on Saturn)

PS2:
Half Life
Contra: Shattered Soldier

PS3:
Resident Evil 5 (my wife especially enjoyed the "Lost in Nightmares" DLC)
Moon Diver (also on XBLA - 4 player Strider FTW)

...Ugh, just a rough eclectic list... I'm at work and can't put as much thought into it as I would like. Tried to exclude the obvious titles and anything that was already listed here in the thread.

[Anapan]

I love co-op games! My brother, my friends, his friends and I have played countless hours of all of these:

NES:
Battle City
Chip & Dale Rescue Rangers
River City Ransom
Battletoads
Snake Rattle 'n Roll

Arcade:
Alien vs. Predator
Simpsons
Gauntlet II
Metal Slug series

Genesis:
Cyborg Justice
Forgotten Worlds
General Chaos
Gunstar Heroes

SNES:
Secret of Mana
Super Smash TV
The Lost Vikings
Kirby Superstar
Knights of the Round
Pocky & Rocky

Saturn:
Radiant Silvergun
Gaurdian Heroes

GC:
Legend of Zelda: Four Swords Adventures

PS2:
Gauntlet Dark Legacy

Xbox 360:
Scott Pilgrim
Protect Me, Knight

Wii:
New Super Mario Bros.

Also, see here for more:
http://www.co-optimus.com/system/13/classics.html

[avrame]

Hmm... I'ma update the first post with the suggestions Should be a nice goto for anyone looking a similar query

[Anapan]

Forgot Jazz Jackrabbit 2 for Windows and MAC.

[SwooshBear]

Did nobody mention Goldeneye and Perfect Dark? Also Portal 2 for something more current.

[swiftzx]

Did nobody mention Goldeneye and Perfect Dark? Also Portal 2 for something more current.

You can't play them co-op in single player. Now the remake of Perfect Dark on XBLA, I believe you can play single player co-op.

[Jrecee]

DKC sort of had co-op. The game still played the same, where one monkey is controlled at a time and you switch between them, but in two player each player controls a different one. So basically the good player is going to play the whole time, until they get hit, at which point the crappy player is going to take over and die.

Knuckles chaotix did the 2 player platformer better, as long as players adhere to the no charmy rule.

[rainnyx4]

Trauma Center: New Blood
Trauma Team

Both for the Wii and are among the best games on the system.

[TidusBlade]

Shadow of the Ninja (NES)
Crash Bash (PS1)
Baldur's Gate: Dark Alliance (PS2)

Dark Alliance has some balance issues but its co-op is still tons of fun.