I must say I've thoroughly enjoyed the co-op as well. A few friends and myself decided to hit up the local internet cafe and play with the co-op mode for awhile and it was a blast. The weapons feel a bit under tuned though, I suspect cause we only had the rank 1 weapons. It also took awhile for people to join, their was only 3 of us and a 4th would have been extremely helpful. I wonder would it be better to purchase the game on xbox for a bigger pool of players?