This game has a lot of problems. The hitboxes are very strange, especially with the baseball bat. You can whack a zombie forever and blood comes out every time you hit it, but you're not actually doing any damage unless you basically let it get right on top of you first. This means a high risk of dying every single time you use the bat, however the game forces you to use the bat CONSTANTLY since it's often the only weapon available, and you lose all weapons after each level (which is insane). Now for the game-breaking part: I got to floor X and couldn't proceed any further, because no key ever spawned anywhere, and I'd already killed all the zombies so I couldn't kill myself and try again.
Game has potential, if it's fixed.