Pretty cool little jam game!
What I didn't like:
Not immediately obvious how much dmg you earn from more slimes (if you did get more after full HP)
Dash as RMB, would have liked shift or something.
Two boss fights, but no real "final encounter"
Theme connections was pretty low
What I liked:
Tutorial
Boss Fights had increased progression in stages
Aiming/Shooting was simple enough
Overall though, it was a fine game. You kept the scope small and polished it. Nice job!