Buff, that's some tight timing. The start of the 5 sliding block was too unstable for me. B can hardly reach that as the first moves away, and as a result the move to the second often makes him land on the rails. But overall well done.
@Block builder Yeah, that part took me some practice. I found that if you time his jumps right as the first block is almost at a stop, then the jump works every time. He lands on the rails if the block has started to reverse direction when he jumps. Edit: Actually if you are trying to time his jumps on the near side, you don't need to do that. You can do his jumps on the far side and still have enough time.
Wow!!! Amazing and very very funny and challenging ability level!! I enjoyed a lot...Thanks @Star Penguin