GROW Cube is part of the GROW series of Flash puzzle games by On Nakayama. As with the rest of the games in that series, you are given a situation with a number of buttons and you have figure out the right permutation of buttons that best fits the situation in order to get the best ending. As you do so, certain elements of the game level up that both serve as visual rewards and clues as to what to do next. For GROW Cube, the situation is to create an attraction out of a cube of Earth.
In this run, Spikestuff uses the fast-forward button to input the permutation of buttons that leads to the good ending as fast as possible.