Hi, first of all, the basic idea is really neat, great puzzle ideas, love to have my brain twisted with this kind of experiments. As most of the others, i too got stuck in the velocity level, but couldn't find any button to skip or 2 buttons combinations as written in another comment. If you can clarify, I would like to test it until the end.
About bugs, those happens, and are not related to your skills: they just become more compley as you improve :-D
I want to focus on a couple : 1) the level with the wobbling door, i had to restart 3 times because sometimes the door went out of the room and I couldn't enter it 2) Sometimes there are visual artifacts, like background tiles carried on (i saw them in the fast level, may be related to that specific level).
But still, you had a strong foundation, with some work may become really interesting to play.