Enter these cheat codes at the Item Select Screen.

     Hidden Items - Hold R1 and press Left, Left, Down, Down, Square, Square, Triangle,
     Circle. 
     99 Items Capacity - Hold L1 and press Left, Left, Down, Down, Square, Square, Triangle,
     Square. 
     Increase Items - Hold L2 and press Left, Left, Down, Down, Square, Square, Triangle, X. 
     All Missions - Hold R2 and press Left, Left, Down, Down, Square, Square, Triangle,
     Square. 
     Enable Japanese Voices - Hold L1 and press Left, Left, Down, Down, Square, Square,
     Triangle, Circle at the mission select screen. 
     Alternate Ayame costume - Press Left, Left, Down, Down, Square, Square,Triangle, Circle
     at the item selection screen. 

You will know that you entered the code correctly when you hear a ninja say "HUH"!

Healing:
To restore your health, pause the game and press Left, Left, Down, Down, 
Square, Square, Triangle, Square. You will know that you entered the code 
correctly when you hear a ninja say "HUH"! 

Debug:
During the game press, pause , then hold down, L1 + R2, then press, up, triangle, down , X , left ,
square, right, circle. Release L1 & R2 , and press , L1,R1,L2,R2. If you intered it right the word "
pause " will disapear. Then un-pause the game and press, L2 + R2. It should bring up a blue
screen with lots to choose from. ( If you go to "charge item", you can get any of the items in the
game, but most are in other language.)