This is a fun little platformer - fairly barebones but fun enough to keep me playing through to the end. A few notes, though! First off, it's a little annoying to have the jump and hover buttons be the same, since it requires letting go of the key, messing with your jump momentum. It'd be nice if there were a second key you could use to trigger the hover, and players could use whichever method they find easier. Also, I don't think you ever mention that the down arrow drops you through platforms, although I personally got it since I've played a lot of platformers.
Anyway, some bugs: a minor one is, on the level menu, you can move the arrow wherever you want, even way off screen. This isn't a huge deal, though. On the other hand, the final boss has a pretty funny and terrible bug. It speeds up every time you hit it, but if you die, its speed doesn't reset. It was so gradual that I didn't realize it at first, but about twenty deaths in, it was absolutely rocketing around the stage. I had to quit out and restart the level for it to be normal again.
Anyway, good job on the game! It could certainly use some polishing, but all in all I think you did well.