Enter m1a2u3l4!? as your name to unlock all of the regular levels in the game.

Enter "greytherat" as your name after selecting a New Game. All levels (even the bonus ones) will be unlocked by doing this.

In level 25 beat Darth Maul to unlock the battle royal mission.

This is more of a glitch than a code. First, throw your lightsaber out in front of you. As soon as you let go of it, press the button combonation for slow motion (L and WHITE). Make the lightsaber go as far as possible by holding L. (The slow motion should quit way before you catch the saber.) When the slow motion quits, press slow motion again and then catch the saber. If done correctly, the entire game will be in slow motion for the rest of the level.

To Kill Darth Maul with just two hits only use the jump and saber slash down move twice. (A button to jump and thrust left analog stick forward to slash down) You can also kill Darth Maul without his lightsaber being sliced in half, when the intermission sequence starts after killing Maul, (when obi-wan force push's him down the pit) you can see the other half of his lightsaber on the floor with the red blade ignited. To do this use any attack apart from the jump and thrust forward move to get his health down low but do not get to the stage where his double-bladed gets sliced in half, then use the jump and thrust forward move, Enjoy!