The new UI addition and the bit in the description (I may have just missed it before...) do a really good job explaining the premise! I got to level 8 before I had to get back to work. It's a lot of fun, a kind of puzzle I don't think I ever played before.
In level 7, I ended up swapping my slow speed to the big block at the top to get back around it, but once I had transferred the 25% speed to the small block that was blocking the exit, I didn't have anything to slow down the big block again! So I just tried to time it as best I can and ran past. It felt like cheating a little, but also like I figured out a secret.
This is some good stuff! I'm glad you kept at it. I gotta say this is LOADS better than the slasher game, and it really seems like something that should have been made for the gameboy.