Epic!
awesome game to play at night. you need super reflex at every second. God work for using the mouse (!) and good luck for the incoming problems and troubles you'll have programing the sequel ... (recommended for the zombie collection)
PS : for the sequel you're working on, you should try to find a way to disable player to use the "shift" button, it get too easy if we can use it (but I never used that technique for the first time beating the game :D)