Really impressive level of detail and polish for this jam! My favorite detail is the animation when you block an attack, but the variety of different enemies and environment pieces is seriously remarkable. I concur that this could easily be expanded on and developed and polished further into a proper little Metroidvania (or just action-platformer) title.
The only real critique I have is the default controls...what kind of hands do you have that make it easy to reach C, F, Q, R, and SPC all at once?! Still, it didn't actually seem to cause me much trouble, so maybe it's my hands that are weird. Awesome stuff!