To eliminate a block from the top of a stack, it must come in contact with a falling monster that matches it. For example, if a Goomba falls directly onto a Goomba block, both will be removed. The player controls Mario, who resides below the playing field and has the ability to swap the positions of any two adjacent stacks at a time. Thus, the player is required to switch around the stacks to ensure that the monsters fall into the correct places. Points are awarded for each set of monsters that are eliminated.