Let's speedrun the game in "all cubes" category
3 years ago(+1)
Let one of the box being pushed through the wall and grab the second one, when you glitch through the wall you will see the box that you don't old next to you but the box you holded disappear, this box is still behind the wall but you still hold it, so walk some distance aways from the wall and the cube should pop in your hand.
3 years ago(+1)
Another way I've found is to stack the boxes in the corner - box jumping up and dropping them works for me - and let them be crushed once to have them align. Then, stand next to the stack so that the moving block will push you first.