Really interesting idea -- I think trying to navigate the zombies once you're there is pretty entertaining. At first I disliked that I couldn't turn the camera all the way around but I think that's a nice touch that makes it a lot scarier once you're in the thick of things, since you have to spend some time to look behind you. Music is awesome as well!
The beginning is way too slow though since you can only move one space at a time, I am getting carpal tunnel from mashing W lol. Also is there actually a win state? I skipped all the zombies by going inside a hill and walking to the end of the graveyard and nothing happened