Nice job, the mechanics work pretty well, loved how you used the assets.
I did fell the game is kinda slow, it takes a while to achieve a fun speed. The game was also not very forgiving with just one life.
Loved it, it was engaging, the controls worked well.
I think some ambient sounds, or a low key music would to wonders for the overall atmosphere. Also if the ammount of zombies could incrise in quantity or velocity, that would fell more challenging, but I kinda loved it that I wasn't chased by zombies, I was hunting them down.