Use the arrow keys to move, press space to collect the bonuses, go to the very far left and press space to go to previous level, and if you die your bonus points will reset. Be careful! You have to get the bonuses in order and if you die with a bonus you can't get anymore bonuses!
Thanks to @okthisisgood for the physics, the rest was me. He says that his platformer tutorial is not up to date, and that the blocks of code he uses are from 2.0, but it works just fine access it at: https://scratch.mit.edu/projects/190579498/. feel free to make a remix. Please alert me of any bugs. I am aware of a the few shortcuts.