The player must take control of a "monster fighter", who must shoot aliens named "Berobero" in the "Space World" without letting them touch him. If he kills three Berobero of the same color as a result, a mysterious alien appears who can be killed for extra points. When the deformation zone in the center of the screen flashes (with the text in Katakana Wāpu in the Japanese version or in the English text "WARP" in the American versions), it is possible that the Monster Fighter is deformed into "Maze World ", where the Berobero must be killed with time bombs. The delay depends on how long the player keeps the button depressed - but each time he kills one, his bombs become more powerful, allowing the Monster Fighter to blow himself up with his own bombs until he returns to Space World.