What you have is a common pacman bootleg that has been hacked to run mspacman bootleg roms, with the maze roms replaced with ms pac attack or possibly even the entire bootleg mspac plus rom set from mame. A real ms pac plus would run on an original midway pacman board with daughter board on a ribbon cable to hold the extra roms. BTW we are still looking for a real ms pacman plus set, the set in mame is a hack and not from a real board.