Multiplayer Characters
Description: Unlock new characters for use in multiplayer mode, insert the following code at the in-game cheats menu: HI9WTPXSUK.

All Reconnaissance Reports
Description: To automatically unlock all reconnaissance reports in the game, insert the following code at the in-game cheats menu: 0ZNDRBICRA.

Kilroy Detector
Description: To activate a Kilroy detector that will alert you when a Kilroy is nearby during gameplay, insert the following code at the in-game cheats menu: 4V35JZHQD6.

Authentic Difficulty
Description: Unlock Authentic Difficulty, beat the game on any other difficulty setting.