Avatar: The Last Airbender

Select the "Code Entry" option on the "Extras" menu to enter one of the following cheat codes.

Enter 34743 as a code.

Collect all the Set Items in the indicated levels to unlock the corresponding bonus.

Level art gallery: Levels 1 through 3.
Character story board gallery: Levels 1 through 6.
Story board gallery: Levels 1 through 5.

You can wait for it to stop attacking, or you can attack it, which will barely affect it. Once it is done attacking, you must attack the sides which turn red.

At first he will shoot fire balls at you. Keep moving left and right, and closer to him. Once you get close enough he will stop and try to hit you with his stick. Take a few steps back and let him try to hit you. Move, and when he stops, hit him. Do this repeatedly until he eventually kneels down. Then, hit him as many times as possible. He will not fight back. When he gets up, repeat the same process until there is a short intermission sequence. He will then use attacks such as curling up in a ball and swinging his bat in a figure eight style on both sides. Wait until he is done and hit him afterwards. In a short time you will defeat him.