Shellshock

Playstation

Debug Menu:
When the Core Design copyright screen appears, quickly press Up, Down, Left, Right, Down, Down, Right, Right, Square. A debug menu will appear.

Invincibility:
Start a game then quit by pressing Start+Select. Now at the Main Title Screen, press Up, Up, Up, Down, Down, Down, Right, Right, Triangle. You'll hear a sound to confirm correct entry.

Bonus Mission:
At the Briefing screen, open the locker and enter the code 4L2CZCQKDAABACQDB. You'll begin the extra mission.

Thanks to Revolution readers Daniel Fortea and Nate Barnes!