It's a very interesting concept.
I found the game difficult because of the mechanics. "E" to shoot wasn't terribly difficult to think about but I couldn't understand how the shooting worked. I clicked the button, a bullet was sometimes shot which was a little annoying because it wouldn't register the shot or the bullet wouldn't spawn.
The enemies were also very fast, so if I died and spammed "X" I would instantly die.
I enjoyed the music and art style.