Unlimited ammunition
Press [Start] to pause game play, then press [Left],
[Right], [Up], [Down], [Up], [Down],
[Black], [White] at the options screen.
Invincibility
Press [Start] to pause game play, then press [Up],
[Down], [Left], [Right], [Left], [Right],
[White], [Black] at the options screen.
All missions
Press [Up], [L], [Down], [R], [Left],
[L], [Right], [R], [Up] at the mission selection
screen in either single player or cooperative campaign mode to
unlock all missions in that mode.
View game developers
When playing in two player mode, go to the mission
where you have to protect Furious Thug. At some point you will
reach a room with a lot of chairs and a jury stand in the front.
Look at the walls until you see some pictures. They appear to
be the game developers.