Remove all of the numbered boxes on each level by reducing their count to zero. A box's number is reduced by one each time your player, the green box, jumps on it so plan your jumps carefully. It's a challenge to complete all 35 levels.
Control the green box by using the left and right arrow keys or the "A" & "D" keys to jump left and right. Use the on-screen arrows to jump left and right on touch devices.