There comes a time in every game enthusiast's life when he or she wants not to fight his or her human brethren, but rather to join forces with a living friend and kick some computer ass.  This might mean killing robots or solving puzzles, or anything else on the killing-enemies-to-solving-puzzles continuum.

    When that time comes, and you're looking for a good cooperative gaming experience, this is the thread you'll turn to.  You will find one of these games, and you will enjoy it.

    Feel free to add more systems, more games, and more descriptions, and I'll keep updating the original post.

 

 

For NES:

8 Eyes
Bad Dudes (The president has been kidnapped by ninjas. Are you a bad enough dude to rescue the president?)
Balloon Fight
Battle Tank
Battletoads
Battletoads and Double Dragon
Bubble Bobble (everybody has to beat this game)
Contra
Chip 'n' Dale's Rescue Rangers
Double Dragon 2
Double Dragon 3
Gauntlet
Gauntlet 2
Guerilla
Heavy Barrel
Ice Climbers
Ikari Warriors
Ikari Warriors II: Victory Road
Ikari Warriors III: The Rescue
Jackal
Mario Bros.
Legendary Wings
NARC
Nightmare on Elm Street (kinda crappy, but has up to 4 player co-op platforming on one screen)
Ninja Crusaders (think like 2 player Ninja Gaiden)
Nintendo World Cup (great Technos soccer)
River City Ransom (this is the one you want, this is the one you want!)
Shadow of the Ninja (think like 2 player Ninja Gaiden)
Silkworm
Sky Kid
Smash TV
Snake Rattle 'n' Roll
Snow Bros
Super Contra (aka Super C)
Super Dodge Ball (great Technos dodge ball)
Super Spike V'Ball (great Technos v'ball)
TMNT 2: The Arcade Game
TMNT 3: The Manhanttan Project
Twin Bee

For TurboGrafx-16:

Bonk 3
Cadash (action RPG, better than Genesis one)
Chew Man Fu (fun little puzzle action game)
Parasol Stars (a third Bubble Bobble game, really good too)

For Genesis:

Altered Beast
Arcus Odyssey (2 player action RPG)
Bonanza Bros.
Contra Hard Corp.
Double Dragon (very close to the arcade original but with a much more stable frame rate)
Forgotten Worlds (port of the arcade game, has a really strange glitch that causes the game to give you game over if you are using 6 button controllers, or have an emulator set as such)
Gauntlet 4
Golden Axe
Golden Axe II
Gunstar Heroes (I can't believe I forgot this, it's so damn sick)
Sonic 2 (it's like 1 and a half players, and 2 players for the bonus rounds, I guess you could trade off Sonic? hey it was fun when I was like 8 or so)
Streets of Rage 2 (great beat 'em up with amazing soundtrack)
Teenage Mutant Ninja Turtles: Hyperstone Heist
Toejam and Earl
Toejam and Earl: Panic on Funkatron
Vapor Trail (basically a Raiden clone, but a good one, plus one of the few co-op shooters on the Genesis)

For Neo Geo:

Aero Fighters 2 (aka Sonic Wings 2 in Japan, a somewhat silly shooter: pilots include a dolphin, a baby, a J-pop singer, a ninja, a goofy robot, and a rich girl with her nanny, great levels and bosses)
Aero Fighters 3 (aka Sonic Wings 3 in Japan, much like the second one, but the structure isn't as good)
Andro Dunos (cool weapon system, though it is probably the ugliest neo geo game)
Baseball Stars 2 (fast action, great animation)
Blazing Star Pretty (horizontal shooter, pre-rendered, cool bosses, great music)
Crossed Swords (sword fighting, leveling up)
Cyber-Lip (called the poor man's Metal Slug, for a reason, but it is an okay game)
Ghost Pilots (vertical shooter, World War 2 shoot'em up, unlike the 194x games it is set over Germany instead of the Pacific, limited power up system, but still good)
King of the Monsters (use a Godzilla clone to beat up a King Kong clone!)
Last Resort (high action horizontal shooter)
Metal Slug
Metal Slug 2
Metal Slug X
Metal Slug 3 (all completely superb amazing co-op run and guns)
Nam '75 (behind the back shooter, tough as nails but a good time none the less, full voice over with a descent main voice actor)
Neo-Turf Masters (the Metal Slug people make a golf game!)
Nightmare in the Dark (Halloween Bubble Bobble-esque game)
Ninja Commando (on foot shooter with ninjas scrolling)
Prehistoric Isle (easy to play, fun to look at horizontal shooters with pre-rendered dinosaurs)
Sengoku 3 (probably the best beat'em up ever, 6 different characters each with their own special moves, a deep and interesting combo system, and it is the best looking beat em up on the system, stay away from all other neo geo beat em ups, they are all ugly clunky and dull, except maybe sengoku 2, maybe)
Shock Troopers
Shock Troopers 2 (overhead run and guns, multiple paths and a lot of characters)
Spin Master (high action platformer, lots of weapons)
Stikers 1945 X (easier and pretty overhead shoot'em up)
Street Hoop (arcade style basketball)
Super Baseball 2020 (power ups, goofy robots, good animation, modified foul and home run zones reduce foul balls and home runs)
Top Hunter Line (platformer, swapping, special moves, some good boss fights)
View Point (someone had the bright idea that co-op shouldn't be the default setting in this one, turn it on in the soft dip screen)
Zupapa (nice cartoony game, Bubble Bobble-esque)

For SNES:

Battletoads and Double Dragon
Contra III: The Alien Wars
Darius Twin (2p shmup Gradius-style)
Firepower 2000
Final Fantasy 3, aka 6 (2p from the beginning, you split your party for battles and can change it at any time, great classic RPG with great soundtrack)
Final Fight 2
Final Fight 3
Joe and Mac
Kirby's Dream Land 3)
Kirby Superstar
Legend of the Mystical Ninja (platforming action with towns in between stages to buy items and train and learn info, hilarious plot)
The Lost Vikings (both great co-op puzzle games by Blizzard)
The Lost Vikings 2
Mickey and Donald (it is Japan only I think)
Mr. Do! (arcade classic with an added co-op mode)
NBA Jam: Tournament Edition
Pocky and Rocky
Pocky and Rocky 2 (2 player action RPGs)
Rival Turf
Run-Saber (basically a co-op Strider)
Rushing Beat 2
Rushing Beat 3
Secret of Evermore
Secret of Mana (2p adventure/RPG after you find the 2nd character, and then 3p after you find the 3rd)
Seiken Densetsu III (Secret of Mana 2)
Shoudai Shin Nekketsu Kouha Kunio Kun (if it has Kunio Kun in the title, it's gotta be good)
Soldiers of Fortune
Sonic Blastman 2
Sunset Riders
Super Battletoads
Super Double Dragon (if you have a short drive, this whole game's like an hour and really fun)
TMNT: Turtles in Time
Top Gear
Troddlers (2p co-op puzzler)
Yoshi's Safari
Zombies Ate My Neighbors (super sweet amazing classic top-down shooter with assloads of enemies, items, weapons, and zings, full of classic movie monsters and then some, highly recommended)

For Jaguar:

Raiden
Total Carnage (same team as Smash TV)

For N64:

Battle Tanx 2: Global Assault
Goemon's Great Adventure (same as Legend of the Mystical Ninja)
Mario Tennis
Perfect Dark (try all the challenges, I dare you)

For PS2:

Baldur's Gate: Dark Alliance
Dynasty Warriors 4
Half-Life
James Bond 007: Everything or Nothing
Lord of the Rings: Return of the King
The Sims
Tenchu 3: Wrath of Heaven
TimeSplitters 2
Twisted Metal: Black

For GameCube:

James Bond 007: Everything or Nothing
The Legend of Zelda: Four Swords Adventures
The Legend of Zelda: The Wind Waker (1.5 players, Sonic 2 and SMG style, controlling Tingle with a GBA)
Lord of the Rings: Return of the King
Mario Kart: Double Dash
Pikmin 2
Star Wars Rogue Squadron III: Rebel Strike
Tales of Symphonia
TimeSplitters 2

For XBox:

Alien Hominid
Baldur's Gate: Dark Alliance
Halo
Halo 2
James Bond 007: Everything or Nothing
Justice League Heroes
Lord of the Rings: Return of the King
Marvel: Ultimate Alliance
X-Men Legends
X-Men Legends II: Rise of Apocalypse

For DS:

Contra 4

For XBox360:

Assault Heroes
EDF 2017
Gears of War
Halo 3
Marvel: Ultimate Alliance
Perfect Dark Zero

For PS3:

fl0w
Pixeljunk Monsters
Resistance: Fall of Man
Time Crisis 4

For Wii:

Metal Slug Anthology
Resident Evil: Umbrella Chronicles
Super Mario Galaxy (1.5 players, like Tails helping Sonic in Sonic 2, but still great fun)
Super Smash Bros. Brawl (co-up SubSpace Emissary, co-op event mode, co-op break the targets, co-op wi-fi)
Trauma Center: New Blood
Wii Play (the tank game)
Wii Sports (tennis)

For PC:
(mostly LAN and/or online, unless noted otherwise)

Age of Empires series
Alien vs. Prediator
Alien vs. Prediator 2
Baldur's Gate
Baldur's Gate 2
CounterStrike: Source
Delta Force series
Diablo
Diablo II: Lord of Destruction
Doom
Doom II: Hell on Earth
Dungeon Siege
Dungeon Siege 2
Full Spectrum Warrior
Gears of War
Ghost Recon
Ghost Recon: Advanced Warfighter
Ground Control 2
Icewind Dale
Icewind Dale 2
Lode Runner: The Legend Continues (2p co-op sharing 1 screen and 1 keyboard, and has a level editor)
Neverwinter Nights
Neverwinter Nights 2
Nox
Operation Flashpoint
Quake
Quake 2
RavenShield
Serious Sam (split-screen FPS on one PC)
Serious Sam 2
SWAT 4
Team Fortress 2
VietCong




    Let's try to keep this list only co-op games and not competitive games. Feel free to keep updating it! This list is becoming super awesome. Feel free to add any consoles or games or short descriptions of gameplay in parentheses after any of them too.  And if there is a group consensus on any of these games sucking, I'll remove it.

    So, VGChartz, what are your favorite co-op games?

I'll have to say Mario Tennis seeing it's pretty much the only one I ever played.

Brawl will be one of them.

NES needs chip 'n dale!

TimeSplitters 2 if you are going to include 6th gen.

Where's Altered Beast? I LOVED that game!

Two absolute classics. Extremely entertaining. Only Golden Axe has really stood the test of time though.

No Contra 3: the Alien Wars?

yep, for nes

Contra
Super contra
Hikari Warriors
Chip and dale rescue rangers
Jackal
and more
let me think