Yu-Gi-Oh!: Sugoroku no Sugoroku Cheats

Kaiberman:
Press Down, B, Left, Right(2), R, Up + R, A at the title screen. You will see the text flash if you have entered the code correctly.

Mutou Sugoroku:
Press Left, Right + B, Right, B, R, Left, Down, A at the title screen. You will see the text flash if you have entered the code correctly.

Yami Bakura:
Press L, Down, Right, Left + B, R, Down(2), A at the title screen. You will see the text flash if you have entered the code correctly.

Yami Yugi:
Press R, Left, B, Right, Up + R, Right, Down, A at the title screen. You will see the text flash if you have entered the code correctly.