From the Main menu select New Game and start a Two-player game. Then during press and hold the R button + X + Y + B and then press the A button using controller one. A message will quickly scroll up the screen when you have entered correctly. This turns on the Jedi Battle Mode which lets you damage player two by hitting them and they can damage you back. To deactivate the mode just re-enter the cheat.

If you should lose all of your lifes you can pause the game and press:

L, R, L, L, R, R, L, R, R, L

You will start at the last checkpoint.

Are you getting constantly surprised by bad guys that pop up out of nowhere? Try this first pause the game and press:

Up, Down, Up, L, R, L

You will activate a Radar screen at the top-right corner of your screen.