The fact that Resident Evil: Raccoon City operation to contain a 4-player cooperative mode is already known, now it was announced that can play like Left 4 Dead in a competing group zombies will. Should be playable: Licker, Hunter, Ceberus and as a special bonus in some sections of a Tyrant, similar to the tank.
The game should not be a simple clone of Left 4 Dead, but also contain elements of strategy. For example, it should be possible to place deadly spider plants or on the route of the opposing team.
Sounds so far very promising and if you think Capcom would have stolen here, should consider this: The game idea Koop against zombies had already previously Capcom with Resident Evil Outbreak. This game unfortunately failed in the not so popular online service on consoles. In any case, now PS3 owners would get the chance to go in the skin of a zombie to human hunting.