Super Pacman title screen.
The term secret gambling games (also known as "stealth gambling games" by MAME developers) refer to arcade games with hidden gambling functions. These games are usually unlicensed versions of other arcade games, including Pac-Man, Space Invaders, and Tetris, often with a drastic downgrade in gameplay, graphics and music. A switch is present in the games that switches the game to a gambling machine. Secret gambling games were often used in areas where gambling was deemed illegal, the arcade portion added to avoid action from law enforcement.
Some other illicit gambling establishments have also known to use a less practical setup involving two PCBs and switch system, one for a seemingly legal arcade game and the other containing the machine's true intentions. In all cases, the secret gambling games by default boot in the game mode.
Known machines
- Cherry Master: Several versions of Cherry Master, a video slot game, feature a port of Ms. Pac-Man, branded as Super Pacman with maze turned to 90 degrees. Another version features Tetris instead. Using a secret input, thee games will boot into Cherry Master (version 8.01 for the Tetris, and 8.31 for Super Pacman version).
- X-Plan: A poker game disguised as an generic aircraft shoot-em-up game created by Subsino, dated 2006 according to MAME. The game features one-button switch intended to be installed "at the secret area, where is most safe and operate easily" in regard to switching modes.
Also known to exist are untitled Pac-Man and Space Invaders clones - the gambling mode reuses sprites from both games specifically. Both are known to run on the same arcade hardware.