At the "Press Start" screen press A, B, Z, X, Y, C. A tone will sound if you did it correctly.

Enable the "Play as Repli and Wolf" code and wait for the tone. Now press A, Z, C, X, B, Y. A second tone will indicate success.

For a secret move, enter the two codes above, then press A, Y, C, X, B, Z. You can now do a secret move by pressing C + Z while playing.