You can jump off of a box when you're grabbed to it, which is why I have the jump direction on the top of the level. Still my bad for not explaining thoroughly.
And I agree, the timing level with jumping onto the platforms is probably the hardest one, since I didn't have enough time to change how the collision worked to make it more lenient. The best advice I can give for it, is to give yourself some sort of visual que, maybe crouching twice right before you're going to move off the button. Even then, it still it very difficult.