Great game! I think this is my favorite implementation of "limited ammo" that I've seen so far. The graphics are charming and cohesive, and the sound design is really on point. I felt that the difficulty was well-tuned, with enough challenge to be interesting but not overwhelming. I might have liked for it to be a bit harder, but I tend to like my games more challenging than most people do.
The only thing I can think of to suggest for improvement is that the dash felt a little jerky and sudden. It worked fine for getting through walls of bullets, but it was just a little disorienting to me.
Despite the warnings I played in WebGL with a gamepad, and had no noticeable issues (I prefer bumpers over triggers for binary "button"-type actions, since I've had triggers break from repeated use).