During gameplay, press DOWN on the Right Analog Stick + UP on the C-Sick, A, X, B, Y.
Fire sword
Press Analog-stick Down + C-stick Up, A, then press B, A, X, Y.
Flame Sword
Hold Up (Control Stick) and Down (C Stick) and press B, A, X, Y.
Get Jack to Wear the Straw Hat
Take Jack to the forest village area. Now leave the controller alone for a few minutes; don't touch any buttons. After a short time Jack will kneel down, pick some grass, and make himself a straw hat. This happens to be the same hat that Jack wears in the actual cartoon. Also, you can fight while wearing the hat until you sustain damage.
Giant Chicken Attack
When you enter the first town of the game there are chickens running around on the ground. Simply chase one of them and slash it with your sword. It will turn into a Giant Chicken and start attacking you.
Lightning sword
Press Analog-stick Down + C-stick Up, A, then press X, A, Y, B.
Max Health Meter
Hold Right (Control Stick) and Left (C Stick) and press A, X, Y, B.
Max Zen Meter
Hold Left (Control Stick) and Right (C Stick) and press X, A, B, Y.