Mappy is an action-platform game for the Sega Game Gear where players control Mappy, a police mouse tasked with recovering stolen items from the Mewkies, mischievous cats. Navigating a six-floor mansion filled with hallways, players use a joystick to move Mappy and one button to open doors, evading the cats while collecting treasures.
The player guides Mappy the police mouse through the mansion of the cats called Mewkies (Meowky in the U.S. version) to retrieve stolen goods. The player uses a left-right joystick to move Mappy and a single button to operate doors. The mansion has six floors of hallways in which the stolen items are stashed.