You have some great art assets here! The game would feel a lot juicier if you took some time to add SFX for player movement and shooting -- with such a broad array of weapons, you'd have quite the interesting soundscape!
I think the process of experimenting with each weapon makes for compelling gameplay, but sometimes the hit-boxes felt random. Given the player movement and enemy behaviors, I would also consider adding knock-back and invincibility frames on damage (to help the player get out of sticky situations).
Death and level transitions were mechanically indistinguishable and felt random -- adding even some simple animations would go a long way toward alleviating this, and would introduce a great deal of clarity to your game.
But all things considered, you made a decent foundation for a solid game. Keep at it! I'd love to play it again when you've had a chance to revisit these ideas!