The player controls a paintbrush and must paint the entire maze in order to advance to the next stage. Two fish–one yellow, the other light-blue–emerge from separate aquariums to pursue the paintbrush around the board, and if either of the fish succeeds in making contact with the paintbrush, the player loses one of three lives.
The player may use two “rollers” to attack the fish. They are located on two overpasses, one vertical in its orientation, the other horizontal. To use them, the player positions the paintbrush on its forward end, waits for either or both of the fish to approach, then pushes the paintbrush along the roller, attacking the fish.
The fish is removed from the maze for a few seconds, then returns to one of the aquariums and resumes its pursuit of the paintbrush. Killing fish in this manner scores bonus points.
The fish initially are dumb, but as time goes on they get “smarter” learning to avoid the roller when the paintbrush nears it, and develop strategies to trap the player between them.
A third character, appearing to be an animal, rolling tire, or invisible man depending on the level, may enter the maze and leave tracks that must be painted over in order for the board to be completed.
The player can limit the damage by running over the figure, which not only stops further tracks from being left but also awards the player a score, which progressively increases as more boards are cleared.