Complete at least one song with a "Platinum" rank in each venue in Showtime mode to unlock the "Cheat Collection 1" option. Then, select the "Cheats" option at the "Extras Menu", select "Cheat Collection 1", then enter one of the following codes to unlock the corresponding cheat option. A sound will confirm correct code entry.

Big eyed character: Press Circle(2), Square(2), Down, Left, Left, Down.
Banana microphone: Press Down, Up, Left, Right, Square, Circle, Square, Circle.
Toothbrush microphone: Press L2(2), Square, Circle, Down, Up, Left, L3.
Dwanye doll microphone: Press Square(2), R3, Circle, Up, Down, Right, Left.

Complete all songs without a "Gold" or "Platinum" rank in each venue in Showtime mode to unlock the "Cheat Collection 2" option. Then, select the "Cheats" option at the "Extras Menu", select "Cheat Collection 2", then enter one of the following codes to unlock the corresponding cheat option. A sound will confirm correct code entry.

Big head character: Press Circle, Square, Circle, Square, Up, Right, Down, Left.
Mercury character: Press Down, Down, Right, Left, Right, Left, Square, Circle.
Wraith character: Press L2(2), Right(2), Circle, Square, R1, R1.
Fish microphone: Press Square, Down, Up, Left, Square(2), L2, L1.

Complete all songs with a "Gold" rank in each venue in Showtime mode to unlock the "Cheat Collection 3" option. Then, select the "Cheats" option at the "Extras Menu", select "Cheat Collection 3", then enter one of the following codes to unlock the corresponding cheat option. A sound will confirm correct code entry.

Small head character: Press Circle, R2, L2, R1, L1, Down(2), Up.
Glass character: Press Down, L2, R1, R2, L1, Circle, Square, Circle.
Oil slick character: Press L3(2), R2, R1, L2, L1, Down, Up.
Ice cream microphone: Press Square, Circle, Square, Circle, R2, L2, R1, L1.

Complete all songs with a "Platinum" rank in each venue in Showtime mode to unlock the "Cheat Collection 4" option. Then, select the "Cheats" option at the "Extras Menu", select "Cheat Collection 4", then enter one of the following codes to unlock the corresponding cheat option. A sound will confirm correct code entry.

Tough Audio Crowd: Press Circle, L1, L2, R1, R2, Right, Right, Down.
Pirate Crowd: Press Down, L2(2), R2(2), Square, Circle, Square.
Robot Crowd: Press L3, Down(2), R1, Circle, Square, Circle, Square.
Zombie Crowd: Press Square(2), Circle(2), Up, Right(2), Up.
Alien Crowd: Press Up(2), Down, Circle(2), L2, R2, Square.