Enter "BAKERSDOZEN" as a profile name to unlock all levels and extras including "Infinite Ammunition", "Super Squad", and "Old Movie" modes.
Successfully complete the game on the hard difficulty setting to unlock the authentic difficulty setting. This mode has no checkpoints, saves, icons nor reticules.
Successfully complete the game on the easy difficulty setting. Choose the last level at the chapter selection screen and play it on a different difficulty setting.
If your character is killed three consecutive times, you will be given a chance to heal any injuries to your squad. To quickly get to this point, intentionally throw grenades at your own feet.