Very good game!
I liked this game very much. The graphics were awesome and there were many kinds of zombies, which made the game harder because some were stronger than the others. The sound was ok. I only think that you should have added a mute button. The game wasn't suposed to be funny, but some of the diary messeges and the notes were very funny.
If you make another one, add the mute button and another game mode, like survival mode. It would be awesome killing zombies without stoping!