Wow. This already feels like a finished game.
The music is awesome. It gives me crazy Cult of the Lamb vibes. The style does, too.
I also really like the gameplay with the different upgrades and especially the combo system.
The only critique I really have is that sometimes it feels like I am getting hit by the boss, even when I shouldn't.
But that's probably because in 2,5D, it's hard to get a full grasp of the actual hitbox of your player.
Nonetheless. This is a great game with lots of potential. Good job!