Unlock all chapters and bonus content:
To get access to all chapters and all bonuses hold Select, go to the chapter 
selection screen and push Right, Right, Left, Left, Square, Square on 
your Ps3 controller.

Unlock bonus interviews:
Finish the game to once to view interviews with veterans Gordon Boulton, 
Sgt. Stan Markut and Sgt. John D. "Bud" Hawk.