Not bad. But needs some work.
Nice work. The animation and graphics are acceptable. Music would be a big plus, I'm sure you'd find something fitting in the audio portal. More sound effects for say, doors opening, or zombie aggression would help a lot for the overall feel of the game. Sadly the controls feel limited and clunky. Being able to move while attacking would help a lot. Being able to jump over enemies would help a lot for the combat issues.
The game feels much to hard on easy.
When you die, there should be some way of knowing what to do next. It took me a while to find the restart button. Maybe a big button that comes up that says "Restart" along with some grim music and text: "You died" would help. Greying out the screen is also a common tactic.
Other than that, it's not too bad. I was unable to get far enough to comment on re-playability.
So good job, but it defiantly needs some work.