Move left or right to direct the cube. It generates a lot of momentum, and is thus difficult to alter direction. Gravity is also rather weak, thus blue bounces quite high when falling onto a floor. Note that you cannot jump. Blue turns grey upon death, which is caused by spikes and falling out of the map. As you progress through the levels, new obstacles appear: Blue blocks can be moved, and usually serve as simple obstacles. However they can end up blocking the way to the finish if you stack them incorrectly. Grey slates are jump boosters. White squares are used to unlock doors, similarly to Flatland. Three holes in the door does not imply needing 3 white squares to open it. Spikes kill blue on impact. You usually have to go around spikes as you cannot jump over them. Red floors are single use; they disappear after impact. Red and blue portals are present in later levels which allow the player to teleport from one area to another.