Other My Sweet Whomp member here, globally agreeing with my teammate : game just looks gorgeous, the mood achieved is super impressive, especially for a gameboy jam game. The little story and world are super charming too.
I also agree regarding the controls. I feel the jump is a bit rigid, nothing too bad since there is no demanding platforming sections, but a nice jump is always appreciated.
Regarding combat. adding to the pushback suggestion, a short hitfreeze (100ms) some flashing on the sprite receiving the hit, and possibly a subtle hitspark VFX would help a lot.
Regarding the combat mechanic in the game itself, I suppose that the time constraint forced you to get rid of a health system for the player, and I guess it's for the best if the alternative was frustrating deaths getting in the way of narration and mood. Still it makes me wonder what combat really brings in this situation, and if, for another project, it might be a good thing to start figuring out that mechanic before adding several enemies and a boss. ^^ Not always easy in jams when everything goes fast and everything seems equally important, I know too well.