PaRappa The Rapper 2 cheats and cheat codes for Playstation 2

Blue hat for Parappa: Finish the game once
Pink hat: Finish the game with the blue hat
Yellow hat: Finish the game with the pink hat

Select level - skip song
Jump to level selection screen, then hold L1 + L2

Unlock doghouse - Song test
Finish the game with the yellow hat. You can listen any songs 
from previously finished stages with cool rating.

Ninja star mode
Jump to level selection screen, then hold R1 + R2
then choose a stage to play in ninja star mode.