One thing quickly; there is a rip-off of this called Rabbit Love Fox. Just thought you might want to know that. This is also a better game than the rip-off.
This is a great game for its simplicity. It pretty much breaks-down zombie survival into a stick-figure-type atmosphere. Zombie survival games are always over-blown and complicated, gorey, etc. This one is different in a way I can't quite find words for.
The movement and play was easy to follow and maneuver. The only thing that kinda bothered me was that there's no control over jump height. Usually if you hold down the jump key, you jump as high as you can, but on this one it just has one big-ass jump that can get kinda irritating if you didn't want to go that high. There are circumstances in which a softer jump would actually be helpful, if not vital.
The guitar playing was great. It flowed well enough that I didn't mind it repeating. I would try to play it myself, but it sounds like you're using full chords. I'm no good at those. Did you actually play the song or was it someone else's?
Lastly, the story was excellent. I love that I didn't figure out I was playing a zombie game until it basically started((I don't usually read descriptions first)). Then the end completely surprised me, probably because I didn't finish the Rabbit Love Fox game. There's always a surprise at the end of a zombie movie, and you pulled it off when she broke out of the cage and I realised I had to let her bite me. It was almost dark how I came to that realisation. No escape, no gun((can't shoot her anyway, thank you for that)), might as well let it happen. Then, in the cheat version, she gets the gun at the end. That made me laugh. Thank you. People like you are the reason I still come back to Newgrounds.