Once you get godmode on this you can do fightnight on this game with zombies. Find a place where you can see and pull out your fist. You can duck and come back up and punch him in the face he'll keep swinging and miss, its actually pretty fun.
What I didn't like about this game is that once you get the chainsaw, you can just run through the game with this thing in front of you. Its like, you don't even know something is there until some blood shows up on the screen.