It's got some good potential, but why are the controls so mixed up? I know you have to use the up arrow key to aim up, but I think this should be used for jumping, since I think a player can live without that ability. I also say that because It's kind of hard when you have to put a finger on the F or Z key and then have one on the spacebar along with the WASD keys if you use them instead of the arrows. Right clicking the mouse would've been the best way to go for shooting controls and the up arrow for jumping. Also, I think it should be four hits before you die instead of two. That is because if you're on a platform above a zombie, when it jumps up to get you it's almost right in your face, not giving you much time to shoot it. Pickups would've been nice, too.