Great style. Great art. Super fun concept. I loved levelling up and getting new powers. Reminded me of Metroid. Getting a power and thinking "what does this do", and then "ooooh... double jump". Full of discovery and exploration. Nice work.
My main feedback would be that the controls were finicky, and it wouldn't have made too much of a difference, but the amount of spikes coupled with finicky controls was very frustrating. I think I died about 135 times in about 5 minutes. And the music would restart every time...
If there weren't so many spikes/deaths, I'd say this is a near perfect game. The controls just need a tweaking.
Great work. Especially for a game jam. I hope you eventually make this a full game.