Enter the passwords at the start screen (you must press select to choose the password entry if you have back-up memory plugged in from your Duo or other means).
Enter these cheat codes while it's your turn during game play.
Enter these cheats while it's your turn during game play.
During the player's turn enter the follwing 2 codes.
NB the clear stage code must be entered and then the player must end their turn for it to work.