PLEASE NOTE: We take no responsibility for any changes you make to your hardware, software, drivers or O/S as a result of the cheats listed here. Only a few of the cheats listed have been tested and we cannot guarantee any of them will work. If you come across a bad/non-working cheat, please let us know and we will remove it.

Alternate ending:
Successfully complete the game three times to hear alternate music during the ending sequence.
Bandanna:
Successfully complete the game after not submitting to the torture. At the end, Meryl will be alive and give you the bandanna. When equipped, the bandanna will allow unlimited ammunition on any weapon.
Camera:
Successfully complete the game to unlock the camera. Use the camera to take pictures to see various extras, such as the faces of the development team.
Control intermission view:
Wait for the message "Camera Change" or "Camera Free" to appear during an intermission sequence. Hold L + R to zoom or C-stick to change the view.
Easy way to kill Mantis
To kill Psyco Mantis easily, plug your controller into socket 4! Now Mantis can't read your mind and you can shoot him!!! He does try to kill Meryl, so kill him QUICK!!!
Eternal Darkness references:
One of the magazines found in the game has a picture of Alexandra Roivas wearing a bikini. Pick it up, open it, then zoom in on the contents to find her. Have a saved game file from Eternal Darkness on your memory card and Psycho Mantis will make a reference to that game prior to the Boss battle. In the Armory, there is a poster of Eternal Darkness in one of the lockers. The poster has a giant picture of a skeleton on it.
Extreme difficulty setting:
Successfully complete the game to unlock the extreme difficulty setting.
Game company portraits:
During the battle with Psycho Mantis, three pictures are hanging behind him on the wall. The people pictured are Shigeru Miyamoto (Nintendo), Hideo Kojima (Metal Gear Solid's creator), and Denis Dyack (Silicon Knights).
Mario and Yoshi reference:
Look on one of the file cabinets in Otacon's office to find statues of Mario and Yoshi. Shoot the Mario statue to hear the classic "extra life" sound, and increase your health. Shooting the Yoshi statue does not do anything except make a sound.
Meryl costume:
Successfully complete the game two times after not submitting to the torture.
Meryl demo mode:
Successfully complete the game after not submitting to the torture.
Otacon costume:
Successfully complete the game two times after submitting to the torture.
Otacon demo mode:
Successfully complete the game after submitting to the torture.
Stealth and Tuxedo costumes:
Successfully complete the game two times with either outcome.
Super Smash Bros. Melee reference:
Have a saved game file from Super Smash Bros. Melee on your memory card and Psycho Mantis will make a reference to that game prior to the Boss battle.
The Legend Of Zelda: The Wind Waker reference:
Have a saved game file from The Legend Of Zelda: The Wind Waker on your memory card and Psycho Mantis will make a reference to that game prior to the Boss battle. Super Mario Sunshine reference: Have a saved game file from Super Mario Sunshine on your memory card and Psycho Mantis will make a reference to that game prior to the Boss battle.
Zone Of The Enders reference:
Look at one of the posters in Otacon's office to see the graphic from the front of the Zone of the Enders: The 2nd Runner box.