The down button is for crouching. The rest of the button combos are for you to find out. Muhahahah Oh, and by the way, you're very fragile, so jumping too high, bonking your head, ramming into a wall, and even looking too ugly can give you a one-way ticket to the ER.
Credit to past me for the Mr. Box Man costume (pls like the title took me a long time) v 1.0- added the basic premise of the platformer with velocity checks for a loss v 1.0.1 added danger where you could lose on and the ability to traverse through multiple levels (I'll give you a hint- the crouching hitbox is slightly longer than the normal hitbox which can let you grab on to ledges)