This game is amazing, the art looks great, and the gameplay is great as well.
My main concern is that the player's hitbox is MASSIVE. I'd imagine that it's the same size as the actual sprite. I suggest making it smaller and more square shaped to make it easier to evade the attacks.
Also, the lack of sound when I take damage makes it hard to tell when I actually take damage. I've been playing Undertale lately and don't actually look at the player when I play- so I can't tell when I'm taking damage.
Otherwise, great soundtrack, great gameplay, great story, and great game. Amazing job!