about the whole hard/too hard thing: the humans seem quite a bit more durable than the zombies, the super powered hulk only shows up towards the end of a mission, the most powerful enemy, the witch, a) does not attack unless attacked and b) tells you which zombie she is by singing, so you know to avoid her, it takes like 2 shots to take down the boomer and the faster zombies, and with the level of cooperation that was built into this game, you probably wont have too much trouble taking care of most undead.