World three hundred and ten is with hard placement of the boxes at the upper right corner.
Step by step solution
Go UP, UP, push RIGHT and RIGHT. Go LEFT, LEFT, DOWN, DOWN, DOWN, DOWN, push RIGHT and RIGHT. Go DOWN, RIGHT, RIGHT, UP, push LEFT, go UP, UP, UP and push UP. Push RIGHT, RIGHT, RIGHT, go LEFT, DOWN, DOWN and push RIGHT. Push UP, UP, UP and UP.
Go DOWN, DOWN, DOWN, DOWN, push DOWN, DOWN, go RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, UP, UP, LEFT, push UP, UP, UP, go LEFT, UP and push RIGHT. Go DOWN, DOWN, DOWN, RIGHT, DOWN, DOWN, DOWN, LEFT, push UP, UP, UP, UP, UP, go RIGHT and push UP. Push LEFT, go DOWN, LEFT and push UP.
Go DOWN, RIGHT, DOWN, DOWN, DOWN, DOWN, DOWN, DOWN, DOWN, LEFT and push UP. Go DOWN, LEFT, LEFT, LEFT, push UP, UP, go RIGHT, RIGHT and push RIGHT. Go DOWN, RIGHT, push UP, UP, UP, UP, UP, UP, go RIGHT, UP and push LEFT.
Go DOWN, DOWN, DOWN, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, LEFT, push UP, UP, go LEFT, UP, UP, RIGHT, push DOWN, DOWN, DOWN and DOWN. Go UP, UP, UP, UP, UP, UP, LEFT, UP, UP, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, RIGHT and push DOWN.
Go UP, LEFT, LEFT, LEFT, LEFT, LEFT, LEFT, DOWN, DOWN, RIGHT, push UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT and RIGHT. Go LEFT, LEFT, LEFT, LEFT, DOWN, DOWN, LEFT, LEFT and push DOWN. Go UP, LEFT, push DOWN and DOWN. Push RIGHT, RIGHT, go DOWN, RIGHT, push UP, UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT and RIGHT.
Go LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, DOWN, RIGHT, push RIGHT, go DOWN, RIGHT, RIGHT, UP and push LEFT. Go UP, UP, push UP and UP. Go LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, DOWN, RIGHT, push RIGHT, go DOWN, RIGHT, push UP, UP, UP and UP. Go DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, UP, UP, UP, UP, RIGHT, RIGHT, push RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP, UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT and RIGHT.
Go LEFT, LEFT, DOWN, DOWN, LEFT, LEFT, LEFT, push DOWN, go RIGHT, DOWN, push LEFT, go DOWN, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, UP, UP, UP, UP, RIGHT, push RIGHT, RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP, UP, UP, UP, go LEFT, UP, push RIGHT and RIGHT.
Go LEFT, DOWN, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, LEFT, LEFT, LEFT, DOWN, DOWN, RIGHT, push UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP, UP, UP, go LEFT, UP, UP, RIGHT, RIGHT, DOWN, push LEFT, go UP, LEFT and push DOWN. Go RIGHT, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, LEFT, LEFT, UP, push UP, go LEFT, UP, UP, RIGHT, push DOWN, DOWN, DOWN, DOWN, go LEFT, DOWN, DOWN, RIGHT, push UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP, UP and UP. Push LEFT, go UP and push RIGHT.
Go DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, DOWN, DOWN, DOWN, DOWN, LEFT, LEFT, push UP, UP, UP, go LEFT, UP, push RIGHT, RIGHT, RIGHT, RIGHT, RIGHT, go DOWN, RIGHT, push UP, UP, UP, UP, go LEFT, UP and push RIGHT.
Go DOWN, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, UP, UP and push RIGHT.
Go DOWN, DOWN, RIGHT, RIGHT, DOWN, DOWN, DOWN, DOWN, RIGHT, RIGHT, RIGHT, DOWN, DOWN, LEFT, LEFT, LEFT, push UP, UP, UP, UP, UP, UP, UP, UP and UP.
Go DOWN, DOWN, DOWN, DOWN, DOWN, DOWN, DOWN, RIGHT, RIGHT, UP, UP and push LEFT. Go RIGHT, DOWN, DOWN, LEFT, LEFT, UP, push UP, UP, UP, UP and UP.
Go DOWN, DOWN, DOWN, DOWN, RIGHT, RIGHT, DOWN, DOWN, RIGHT, RIGHT, UP, UP, UP, UP, UP, LEFT, LEFT, DOWN and push LEFT. Go RIGHT, UP, RIGHT, RIGHT, DOWN, DOWN, DOWN, DOWN, DOWN, LEFT, LEFT, LEFT, LEFT, UP, UP, UP, push UP and UP.
Congratulations. You have completed world three hundred and ten. Get ready for world three hundred and eleven.