At the beginning of the game, the zoobies in the upper left corner of the screen is used as the matching-area. Click the zoobie in the lower right corner of the screen to change the type of zoobie in the matching-area. If there are zoobies of the same type around, they will be merged to form a larger matching-area. If you match all zoobies within the number, you can enter the next level, otherwise game over.