Neat game. There's a lot more potential for puzzles than you covered here, but thanks to the high pacing the game stays interesting regardless. Also, I like how dymanic the art is, but it could really use some nicer colors. It also feels off that the walls have depth (dark & light highlights) but everything else doesn't.
Btw, I had no idea that you could change the game speed in every level, I thought you had to decide in the menu. It really would've helped me out, as I sometimes found the platforming a tad too difficult.
A speedrun option would work quite well (though how you deal with the different speeds is a different story).