Ben 10: Protector of Earth Cheats

The Menu
[A], [B], [X], [Y], [L], [R], [Select]: Galactic Enforcer Skin
[Left], [Right], [Left], [Right], [L], [R], Select: Gwen 10 Skin
[Up], [Right], [Down], [Left], [A], [B], [Select]: Ultra Ben Skin
[A], [Left], [Y], [Right], [X], [Up], [B], [Down], [Select]: Unlock Upchuck
[Left], [L], [Right], [R], [Up], [Down], [Select]: Unlocks bonus mission

Invincible Ben!
Must be Ben in-game and then press:

[A], [Left], [A], [Right], [A], [Left], etc: Make Ben ALMOST invincible.

Master Control
Beat the game once, then continue collecting all 30 sumo slammer cards. With that done, enter any level with "Insane" level. The Master Control will be activated, which allows unlimited Omnitrix battery, and switch in between aliens without reverting back to the human form.

Master Control: Collect All 30 Sumo Slammer Cards

Omnitrix Aliens
Complete the levels below to unlock these Omnitrix aliens:

Cannonbolt: Complete Hoover Dam
Wildvine: Complete Seattle Space Needle
XLR8: Complete Grand Canyon