The music is awesome. I really liked the vibe you were going with.
Regarding the gameplay I noticed a few things:
Unless I missed somehing, shooting in only 2 directions was a struggle in a survivor-style game. I wished I could shoot in more directions.
Also, I felt like the collisions of the enemies could be removed. In one attempt I ended up cornered between enemies and a wall and was not able to move. So I stood there and had to wait.
Apart from the things mentioned, I think you did somehting cool and make sure to keep up the good work! :)