I love the graphics and animations. I like the movement. It feels good. Jumping feels good.
Sometimes I wasn't sure why I took damage, it seemed like the ghosts formed an attack just when I was landing on top of them. I guess that's fair, but it felt like the wolf should have won in those situations, especially on easy mode. (Maybe that would make it too easy, IDK)
I'm curious if you tried or considered a version with no health or player death. Obviously it'd be more casual, and you need some penalty for failing to time jumps correctly, but maybe a time sink like losing your collected energies would serve the game as well as a death mechanic (probably just for super-easy casual mode.)
Nice job implementing an upgrade system in a jam game. Great submission!