I believe that “people in same teams” doesn’t automatically make a game cooperative. For example, in Rogue Spear that I played… at some point I started to be skilled enough to try “ramboing” in one level, running to the other house and those some grenades and pretty much take all the 5-6 enemies (did that once). Meanwhile other teammates were lurking behind some walls.
Sure, there was also options to go in a team… but was it cooperative? Sometimes perhaps, sometimes perhaps not so.
Left 4 Dead is said to be a cooperative shooter, and there’s truth in this. For example, if you go solo, you end up in ground with zombie hordes all around you. Or one of the boss zombies catches you, and you need a teammate to aid you. There’s several things where a teammate is needed. It could be classified as a cooperative since you need others in order to win.
NHL ’10 drops somewhat in the same category: you control one player on the ice, and for example scoring goals is much easier when there’s other team mates making solid passes. You can try play solo, but playing in team is more effective.
Which gets me to the point of what “cooperative” – to me – means in game.
Cooperation means that two (or more) players need others to help them out or they cannot proceed any further. In Army of Two this means helping the other guy climb up, who can then help you climb up. In Battlefield one guy can drive the tank, while other guy is in using the tank machine gun. In several games, there’s unique roles where each player needs to take part and help the whole team to survive.
Being in a same team doesn’t automatically make a game cooperative. But games that support situations where people can support each other. This makes a game cooperative, and usually fun too, in my pretty humble opinion.
If you have more examples on cooperation in games, please feel free bring ’em here.