Wow, this is insanely polished and content rich for a jam game! There's a huge number of levels and they all seem quite well designed. There's a hub world, option collectables, unlockable outfits and everything. The art is very detailed for such a small resolution. The music/sound fx are great too and feel high quality.
The controls feel nice and the mechanic of bouncing off things with the sword is interesting. As others have mentioned though, it could be tweaked to be a little more forgiving e.g. smaller spike hitboxes. I'm not sure if there's an end goal beyond "complete all the levels" but I managed to collect enough items to open all the locked doors.
Overall, an incredibly impressive job! It feel like something I could see on Steam for a few dollars.