World one hundred and fifty-three is with thirteen boxes, but not very difficult.
Step by step solution
Go UP, LEFT, LEFT, UP, push LEFT, LEFT, LEFT and LEFT. Push DOWN, go LEFT, LEFT, UP, UP, UP and push UP. Push RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP and UP. Go RIGHT, UP and push LEFT.
Go DOWN, DOWN, LEFT, LEFT, LEFT, DOWN, LEFT, DOWN, DOWN, DOWN, RIGHT, RIGHT, UP and push LEFT. Push UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP and UP.
Go DOWN, LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, DOWN, RIGHT, RIGHT, UP, push LEFT, LEFT, LEFT, LEFT, LEFT, LEFT, go DOWN, LEFT, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP and UP.
Go DOWN, LEFT, LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, RIGHT, RIGHT, RIGHT, DOWN and push LEFT. Go DOWN, DOWN, RIGHT, RIGHT, RIGHT, RIGHT, push UP and UP. Go LEFT, UP, LEFT, LEFT, LEFT, LEFT, LEFT, DOWN and push RIGHT. Go UP, RIGHT, RIGHT, RIGHT, RIGHT, DOWN, RIGHT, RIGHT, UP, push LEFT, LEFT, LEFT, LEFT, LEFT, LEFT, go DOWN, LEFT, push UP, UP and UP. Go LEFT, UP, push RIGHT, RIGHT, RIGHT, go UP, RIGHT and push DOWN, go RIGHT, DOWN and push LEFT.
Go UP, LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, DOWN, DOWN, DOWN, LEFT, push UP and UP. Go RIGHT, UP, push LEFT, LEFT, LEFT, LEFT, LEFT, go DOWN, LEFT, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, go UP, RIGHT and push DOWN.
Go LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, UP and push UP. Go RIGHT, UP, push LEFT, LEFT, go DOWN, LEFT, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT, go UP, RIGHT, RIGHT, DOWN, DOWN, LEFT, push UP, go RIGHT, UP, push LEFT and LEFT.
Go DOWN, LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, RIGHT, RIGHT, DOWN, DOWN, DOWN, LEFT, push UP and UP. Go RIGHT, UP, push LEFT, go DOWN, LEFT, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT, go UP, RIGHT, RIGHT, DOWN, DOWN, LEFT, push UP, go RIGHT, UP and push LEFT.
Go DOWN, LEFT, LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, DOWN, LEFT, push UP and UP. Go DOWN, LEFT, LEFT, UP, LEFT, LEFT, UP, UP, UP, RIGHT and push DOWN. Go RIGHT, push UP, go DOWN, LEFT, LEFT, DOWN, DOWN, RIGHT and push UP. Go DOWN, RIGHT and push UP. Go DOWN, DOWN, DOWN, LEFT and push UP. Go RIGHT, UP, UP, LEFT, LEFT, DOWN, push RIGHT, go UP, RIGHT and push DOWN. Go LEFT, DOWN, push RIGHT, RIGHT, RIGHT and RIGHT. Go UP, UP, UP, LEFT, push DOWN and DOWN. Go RIGHT, DOWN, push LEFT, LEFT and LEFT. Go DOWN, LEFT, push UP, go RIGHT, UP, UP, LEFT, LEFT, DOWN and push RIGHT. Go UP, RIGHT, push DOWN, go LEFT, DOWN, push RIGHT, RIGHT and RIGHT. Go DOWN, RIGHT, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, go UP, RIGHT, push DOWN, go RIGHT, DOWN and push LEFT.
Go UP, LEFT, LEFT, LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, DOWN, RIGHT, RIGHT, UP and push LEFT. Go DOWN, LEFT, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, go UP, RIGHT, RIGHT, DOWN, DOWN, LEFT, push UP, go RIGHT, UP and push LEFT.
Go DOWN, LEFT, LEFT, LEFT, LEFT, LEFT, UP, UP, LEFT, push DOWN, DOWN, DOWN and DOWN. Go RIGHT, DOWN, push LEFT, LEFT, LEFT, go DOWN, LEFT, push UP, go RIGHT, UP, UP, LEFT, LEFT, DOWN and push RIGHT. Go UP, RIGHT, push DOWN, go LEFT, DOWN, push RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, go UP, RIGHT and push DOWN.
Go LEFT, LEFT, LEFT, LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, UP, LEFT, LEFT, UP, UP, UP, RIGHT, RIGHT, push DOWN, DOWN and DOWN. Go LEFT, DOWN, push RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT and RIGHT.
Go LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, UP, UP, UP, UP, LEFT, UP, UP, RIGHT, push DOWN, DOWN, DOWN, DOWN and DOWN. Go LEFT, DOWN, push RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT and RIGHT.
Go LEFT, LEFT, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, LEFT, UP, LEFT, UP, UP and push RIGHT. Go UP, RIGHT, push DOWN, DOWN, DOWN, go LEFT, DOWN, push RIGHT, RIGHT and RIGHT. Go DOWN, RIGHT, push UP, UP, UP, go LEFT, UP, push RIGHT and RIGHT.
Congratulations. You have completed world one hundred and fifty-three. Get ready for world one hundred and fifty-four.