GameBoy Advance Cheats: Invincible Iron Man, The Cheats

Invincibility
At the main screen, press Right, Up, Left, A, Right, Select.

Unlimited chest plate blasts
At the main screen, press B, A, Left, Down, Up, Right.

Powerful close-range shots
At the main screen, press Up, Down, Left, Right, B.

Level Select
Successfully complete the game to unlock the 'Level Select' selection at the options screen.

Gallery
In order to get complete the gallery option, you must collect all eight images, each in every stage.