Perhaps a "hacky" solution would be granting the multi-jump power-up before you jump out of the clouds? That would allow for you to reach your destinations faster or skip sections entirely, with basically no refactoring.
Also, if you ever want to add a 6th ending I really wanted there to be more to the creepy guy who gives you the running power-up. I noticed he disappears when you give the wood to the fire, but he leaves behind a "hole", or some kind of black space, which could easily be a door to... somewhere.