Various Cheats
     Start  the  game with the command-line parameter, '-cheatenable'.
Then during gameplay, press any of the following:

F2                      God Mode
F4                      Infinite Ammo
F5                      Normal View
F6                      Observe View
F7                      Fast Level Restart
F8,F9,F11,F12           Texturing Modes Switching

Get the Stealth Suit
     Submit  to  Ocelot's  torture,  then after you have completed the
game,  save  your game. Then load that saved game to start at the dock
with the Stealth Suit.

Get the Bandana
     Do  not  submit to Ocelot's torture, then after you have complete
the  game,  save  your game. Then load that saved game to start at the
dock with the Bandana.

Tuxedo and alternate Cyborg Ninja Armor
     Beat  the  game  twice,  then save your game at the end. Now load
that  saved  game and Snake will change into a Tuxedo in the elevator.
Once you get to Gray Fox, he will have different colored armor.

Psycho Mantis Tricks
     To  make  Psycho Mantis unable to predict Snake's actions, use an
alternate  controller  to  fight  him.  This  works best if you have a
gamepad and a keyboard.