Some really good with a few bugs to fix.
The good: The art, music and sound are all great. Love the ligh effect and the music is erie. The zombies give a nice shuffle and moan. Everything fits art wise.
The gameplay is good. A mix of unlimited melee with a shotgun and grenades for a real punch. I like how zombies bounce (they will fly backwards like pool balls of you hi them). I love how they shuffle predictably towards you. Giving you the tactical edge to think about drawing them around a corner a couple at a time.
The bugs: I spent most of the game spamming the melee button. This was a great way to beat up zombies but seemed to give my movement unexpected side effects. I wanted to creep forward swinging my crowbar like Gordon freeman. What I would tent to do was to start skating forward as if I had the key held down. I would move forward into the enemy hord and shortly there after to my doom. The other bugs involved the bouncing zombies. I noticed that if there was a hord moving round a corner in something like a backwards L shape, I could shoot the bottom of the L and the entire hord would die. As if the impact caused a chain reaction to the zombies that were still out of sight.
It feels like a beta. Something to iron the kinks out of. It is playable and pretty fun. The problem is the controls (could be a firefox thing) and the lack of any health indicator make the gameplay kind of frustrating as it can be hit and miss. Tune those up and you have an easy 5/5. As is are can only carry you half the way.
Keep it up.