Level Select 
     At  the  main  menu,  press  Triangle,  Circle, Triangle, Square,
Triangle, Circle, L1 + R1.
 
Unlock All Costumes 
     At  the  main  menu,  press  Triangle,  Circle, Triangle, Square,
Square, Square, L1 + L2.
 
Unlock Debug Menu 
     At  the  main  menu,  press  Triangle,  Triangle, Circle, Circle,
Square,  Square, Circle, Circle, L1+ R1 + L2 + R2. The Debug menu will
be available from the pause screen.
 
Unlock all Cerebro Files 
     At  the  main  menu,  press  Triangle,  Circle, Triangle, Square,
Square, Square, R1 + R2.