It's sad you couldn't finish the game, but that is how game jams often go; I don't remember the last time I actually implemented my initial plan.
Regardless, you have some nice polish for your combat. The SFX you've added provide important feedback for the gameplay, and the stagger and knockback upon being hurt, adds weight to taking damage, and avoids it potentially going unnoticed in the bullet hell mania.
Neat game, and cool concept for the theme. More upgrades would have been nice, but a "vertical slice" of gameplay isn't so bad either.