That was a fun little game! Graphics were nice, movement was smooth, and that track was fire! I think my biggest problem was that fire was "R" instead of "E" or Spacebar or something. I kept getting up close to a zombie and forgetting I had to skip a button to hit the right key, which led to my death on more than one occasion. Besides that, it was really nicely put together.
I did catch one little bug.... I jumped from the top of one platform and landed on top of a ladder, and my character proceeded to climb all the way down it without having to hit "S." I think you must have programmed your own gravity, using downward velocity until you hit the ground, and the same thing for hitting "S" while on top of a ladder. If that's how you did it, you could probably stop it by saying something like "If player is on ladder and S is not held down, downward velocity = 0."
Really fun, though. I'd play a full-length version like crazy.