Huh.
Well, it's been done before a million times, but that doesn't bother me. What does bother me is that it adds nothing new and doesn't do anything as well as those other identical games. I can't be kind to this, since I simply didn't find it fun enough to play. It's not un-salvageable though, so keep trying. Everything else I've already seen mentioned, but the collision detection is particularly bad. It's like the zombies have an invisible force-field of pain around them, which combined with the fact that you take damage constantly when you're in contact with one means you die way too easily.