I actually fricken loved this! I think I possibly just found my new fav game of the jam!
I loved that the movement of the character was quick and snappy and the wall jumping was easy enough.
I loved that the mechanic of throwing/catching the ball had multiple implications; it allowed you to kill enemies, allowed you to jump again, allowed you to become a platform for future iterations, and also required you to plan around where it was going for the multiple iterations. Seriously loved it, brilliant game design.
It was super fun! Sure, it was challenging, but I think a game like this needs to have a decent degree of challenge. Perhaps the hit detection could be slightly more forgiving, but maybe not, maybe its great just as it is (at first i thought it might be abit TOO precisse, but mid-sentence i thought "well i did finish it afterall, which I can't say i've done for all the games i've played in this jam").
Graphics and audio were very nicely polished, had good amounts of juice in it for a game jam game.
Usually I go into depth with what could be improved, but I am actually struggling to find faults with this game. Perhaps allowing the player to scan the level before starting may be a nice touch. Perhaps having a couple of visual markings on the level background to help line up a target (e.g. if there were little blemishes on the wall and i threw the ball at one from a particular spot and the ricochet JUST missed the enemy then I would know to aim slightly higher/lower to that blemish next time). These are pretty minor improvements obviously though, which is a credit to how good I think your game is.
The only thing I noticed which would be a bug is that crossing out the sound/music buttons on the menu didn't seem to actually stop the music.
I can't emphasise enough how much I liked your game, I think this has good potential to be a real game with more levels. Now go review more people's games so they are tempted to play yours, because yours deserves more views/reviews than it has.