As in "Mr. Do!", the player can earn an extra life by collecting all of the letters from the word "EXTRA". Regular monsters can be changed into monsters bearing the EXTRA letters by collecting all three keys distributed around the playfield and then picking up a magic shield from the top floor. Monsters in this state are easier to defeat than normal; a simple hammer strike will do the job. After a brief interval, they change back into their normal forms. The game also offers a bonus credit for collecting a rare diamond that appears on the playfield at random intervals.