If you want solid 4-player Co-Op and lots of stuff to do, get Resident Evil: ORC. I've unlocked 35/50 achievements in the few days I've owned it. Almost ALL of them are easy peasy to get. Plus the gameplay is just fun, I've played the Campaign so many times now I can't count. And I'm still not bored of the (only) 7 missions you have.
Multiplayer is really fun, but you have to make sure you have good guns and abilities. Everyone else does, lol.
EDIT: And a special Spec-Ops campaign line DLC is coming on Wed. for FREE!
