Invincible Oscar
While playing the game, press Back, then hold L and press A, B, A, Left(2), X, R, Down, X(2).

Two extra Clams and fame
While playing the game, press Back, then hold L and press B(2), A(2), B, A, B(2).

Attack mode on at all times
While playing the game, press Back, then hold L and press B(4), A, B(3) or B(4), A, B(4).

Replace all Pearls with Fish King coins
While playing on any level with Pearls, press Back, then hold L press B, A, B(3), A, B(2).

Completing dance mode
To complete dance mode easier, press A + X + B + Y on each arrow; it will count as the arrow it is pointing to, even doubles.