At item selection screen, hold R1 and press Left, Left, Down, Down, Square, Square, Triangle, Circle
All ninja tools
Equip armor at item screen then enter left, left, down, down, square, square, triangle, circle
Alternate Ayame Armor
Pause the game, hold L1 + R2 and press Up, Triangle, Down, X, Left, Square, Right, Circle, then release L1 + R2 and press L1, R1, L2, R2, then wait a bit and press Start, L2 + R2
Debug Mode
At the select stage menu hold R1 and press Left, Left, Down, Down, Square, Square, Triangle, X
Enable enemy layout selection screen
At the items menu hold L1 and press Left, Left, Down, Down, Square, Square, Triangle, Square
Increase item capacity to 99
At the item selection screen hold L2 and press Left, Left, Down, Down, Square, Square, Triangle, X
Increase Items
At the mission select screen hold L1 and press Left, Left, Down, Down, Square, Square, Triangle, Circle
Japanese Voices
Pause the game and press Left, Left, Down, Down, Square, Square, Triangle, Square
Refill health
At the stage select screen hold R2 and press Left, Left, Down, Down, Square, Square, Triangle, Square
In the ninth level, Reclaim the Castle, is a big shorcut which is not supposed to be in the game. Climb to the first roof of the castle and go on the very edge. Make sure you don't fall off. Pull out your grappling hook and aim it straight up and shoot it. If you were close enough to the edge when you did this, your character will grab on just below the spikes. Pull yourself up and pull yourself up again. Walk forward to begin the boss battle. This glitch lets you skip the 20 or so enemies that you normally would have to fight.