You can move the falling pieces (windows) to the right, left, or down with the buttons. Pieces (windows) are scored differently for each color: black is 100 points, white is -10 points, and red is -20 points. Scores are added by erasing these pieces (windows). If the score becomes negative or the pieces (windows) overlap to the maximum of the stage, the game will be over. Compete to see how many points you can score within the time limit. Also, if you erase 5 or more red pieces (windows), you will enter the back mode. In back mode, the falling speed of the pieces (windows) is accelerated.