Overall the graphics, animation and the lighting is excellent! Also the hand drawn bit e.g. [E] is pretty neat. The sound design is also great! I liked the music that the radio plays.
I wish either there was a variety in zombies, or the ammo was cheap. The game could be a lot faster to give a feeling that your house is under attack making the game a bit frantic such as increasing the reload speed.
While the concept is excellent, the game tends to get a bit repetitive after a while. I think it could benefit greatly from relooking at the game economy.