This is SUPER polished!! It feels like a demo to a complete game, which is really really good for a game jam entry.
I accidentally found some cheese really early on though that made the difficulty of the game really trivial, though. If you jump and then press z -> x in quick succession, you can functionally create infinite platforms for yourself and ascend upwards anywhere. If this cheese was addressed somehow, I could totally see this being converted into a full 1hr experience or something if there were more levels :)