Here are some cheats and tips for the game Ghosts And Ghouls.
More credits:
Press Up, Up, Down, Down, Left, Right, Left, Right, I, II at the “Push
Run Button / 1 Player Only” screen. Up to nine credits may now be
selected for game play.
Options menu:
Hold I and press Run at the title screen. Game settings, player number,
and sound test options will now be available.