Hey, not bad at all!
When I started playing I expected it to be a bad game. To tell you the truth I usually judge a game by it's looks. But when I started playing I thought 'this is my kind of zombie game'.
There are some things I disliked though. For example, bullets are too expensive. I assume you want players to aim and shoot carefully, but this isn't what I did. Because of the fact that every bullet goes through the zombies, I just kept moving arround until they all were together and then, I shot them and they all died together. It's kinda absurd :P
I think the environment is a little empty, and that you could add some things to it. For example, a car, making you think that is how the protagonist ended there.
I don't know if you'll improve it or if you will just leave it like it is, whatever you do, it's better than I inicially expected.