The art is massively cute. The boss looked great. Love the lighting torch mechanic.
I love metroidvanias, so you got me right off the bat.
As far as improving, really it's all about time and play testing which we don't have as much during these jams. The controls and collisions get a little wonky at times, I'm sure you're aware. Many times I got stuck on corners, that kinda thing. I mostly just blame playing on the keyboard, haha!
The music is nice. Seamless looping except for the boss. Some of the sound effects could be raised/lowered in volume. Like, the landing is much louder than the jumping and can end up being a bit distracting.
Again, everything is great so far, these are just little nitpicks.