Copying my comments from the game page. Great job on this Asterisk, I had a lot of fun!
In terms of improvements, I would probably gradually scale up the difficulty, right now the jump between Levels 1-3 is pretty extreme. And since this is a game for experienced platformer players, I would recommend making the first few levels a little hard to help with that >:)
I also noticed that holding space bar allows you to slide up walls, which was a cool feature but the physics of it felt a little finicky at times. Maybe clamping the speed when sliding would help make that more predictable.
Other than that, I'm loving the game!