You got the metroidvania feel perfectly. Graphics are cute, and animations look nice and smooth.
- Sometimes the ranged attack gets bugged and doesn't shoot at all, but a couple of seconds after all the shots appear together like they had lag.
- After a Game Over screen level's music never plays again.
- Boss needs some kind of health bar to see how much you have damaged it.
Enjoyed it a lot and can't wait for the next demo. Good job!