The 'Nightopian Collection' becomes available at the 'Main' menu when you complete Christmas NiGHTS with Elliot and Claris. This option displays the Nightopians, Mepians, Nightopian and Mepian eggs in each level along with the mood of the Nightopians and Mepians in that level.
At the 'Title' screen press Left, Right, Square, Circle, X, Triangle, R1, R2, Down, Up, L1, L2 to unlock ALL bonuses. If you entered the code correctly a message will appear on screen as confirmation. When this code has been enabled you will not be able to earn trophies or upload your highscore.