I really like pixel games but I feel like this one doesn't have very many colors. If you could maybe add some colors, that would be great but if this was suppose to be one of those retro games without color, then that is fine with me.
The things that mark where you have died shouldn't disappear and reappear really fast. I feel like that could cause seizures to some people and it just doesn't look nice.
Other than that, I thing this is a great game with a good soundtrack. Keep up the good work!