As you know, I played through this one yesterday. Thanks again for the help! :)
I had a lot of trouble with the timing of the first horizontal boost block, but once I got it down, it was pretty much smooth from there. The world 2 levels were so much fun, incorporating the gravity switch with the moving platforms! I especially liked the one where you kind of had to stack things on top of each other to make the jump across possible. Really nice puzzle design; just enough to make you think without being overwhelmingly hard. At first I thought the player having such a short jump was going to be limiting, but all the platforming challenges were nicely tuned around that.
Also, just when I was starting to think the music was getting a little repetitive through worlds 1 and 2, world 3 came along and blew my socks off; such a cool piece of music, and I absolutely love how the platforming synced up with the tune. World 3 was also by far the hardest platforming challenge, which was a really nice way to cap things off.
Also, the art is really cool. The dithering is great, and I love the tiny little bit of shadow the protag adds to the dither pattern around them; such a cool little detail. And I love the squash/stretch on the protag. Just very nicely done.
All-in-all, I really had a blast with this one! Great work :)