Basic but really enjoyable. The smooth movement and high framerate made trying to "speedrun" the game on my second playthrough very enjoyable. It's a shame the music wasn't made for this game, because it was very fitting.
I think the game could be improved by having a level counter, and well as a real end screen instead of a glitched infinite post-game level. I also don't know if the ability to jump infinitely many times is a bug or not.