When at the STAMPER menu hold L1 + L2 + R1 + R2 + Left + Circle + Triangle + Square and press X to show a menu where the cheats have to be entered. The cheats below have to be done at the screen.
Hidden Sound Clips
Open the Sound Test option and listen to the first six sounds. After Tiny will start blurting out trivia and other weird things after the instructions and normal reports.
Write in WEAKROBOT.
Write in FEATHER.
Little Tiny Tank
Write in TINYTINY.
Start a new game, in the STAMPER menu, press and hold L1+L2+R1+R2, Left, O Select.