When you press jump within 100 milliseconds (approx) of leaving the ground, you can still jump. This can extend the jump, most notably allowing a skip in level 5.

There's a possibility of a small time save in level 4 (Probably not worth actually doing even if it is a time save though).I thought I'd throw this out here to see what people would come up with.

I knew you could jump over the ghosts, but never knew it could be done consistently for RTA. Nice video! You should put it in the guides.