Good one! I related the sprites to Celeste at a first sight. The art is nice and the UI is made with care, which is a nice achievement. I kept playing for a while and had fun with it.
I noticed that sometimes the gun stopped shooting, my first guess was that it was failing but after I imagined it could be that it ran out of ammunition. If that was the case, I'd suggest the UI to inform it anyhow.
I enjoyed the idea and the sounds as well.
Well done, keep up the good work!