Love the art and effects, makes the movement and attacks feel really punchy.
Seems really difficult at the moment. One suggestion would be to add knockback on the enemies when you shoot them. You could also just add more health. I didn't make it to a shop if there was one -- does the shop have health?
It's interesting how the game plays out, because it's actually more about jumping over enemies than shooting them. I think the really good effects on the shooting (compared to the relative lack of "punch" on the jump) made me subconsciously focus on shooting over jumping when I first started playing, which didn't end well. So maybe adding knockback is a bad idea since it'd make things too easy.