Various cheats
  
Unlock all gadgets:
     At  the mode select screen, hold R1 + L1 + R2 + L2, then enter 
Go Wild! as a password.

Disable all gadgets cheat:
     At  the  mode  select  screen, hold R1 + L1 + R2 + L2, then enter
Limited! as a password.

Hard mode:
     At  the  mode  select  screen, hold R1 + L1 + R2 + L2, then enter
Hard! as a password.

Normal Mode:
     At  the  mode  select  screen, hold R1 + L1 + R2 + L2, then enter
Normal! as a password.