While at the Cheat Screen (in the Setup Menu), press Start, A, Y, X, X, Z, Z, X, Y, A, Start.

Conversation Mode

While at the Cheat Screen (in the Setup Menu), press Start, Z, A, Y, X, Z (3x), Start.

Invincibility

While at the Cheat Screen (in the Setup Menu), press Start, A, A, Y, Y, Z, Z, X, X, Start.

Turbo Mode

While at the Cheat Screen (in the Setup Menu), press Start, Z (10x), Start.