Um Jammer Lammy cheats and cheat codes for Playstation

Unlock extra Parappa stages:
Finish the game once, then go back to the stage selection screen.
Press Right until the extra Parappa stages appear.

Unlock Lammy and Parrappa 2-player levels:
Finish all extra Parappa stages.

Special menu
Finish all stages in the game, including the Lammy and Parrappa stages.
After that, choose the "Special" option at the title screen to 
access to a new menu. Go to the new menu. You can play all music 
and the game charactes will dance under your control.

Customized lyrics and notes
Load the game, then immediately reset your PSX when Lammy appears at 
the title screen. After that, allow the game to reload. You will find 
a new menu next to Lammy's guitar at the title screen. You can customize 
the notes and lyrics by using those new options.