Change Parappa's Voice
Complete the first two levels with a "Cool" rating. Then, press X(3), Triangle,
Circle, Triangle, Square(2), Right, Left, Square, X and finish the next level as
usual. On the level 4, press X, Square, Triangle, Circle, X to allow Parappa's
voice to be changed. Hold R1 and press Circle or Triangle to cycle through the
voices of the other characters in the game.