Ok I see what you were going for and the game is hella hard that way. Unfortunately I don't have the will or the time to master it. I've been trying for some time but the moment where the two boxes fall from the top platform at once is just too hard for my level even when I try to recoil myself left to avoid the place they'll fall onto. After that I just gave up and played with two hands to see what else is in the game. And what I found out is there's no way I could finish it with one hand. It's quite an original idea but it might put off a lot people. But I suppose you're going for hardcore.
Even though the game is about boxes, shooting is really juicy.