Start the game with the "mgsi.exe -cheatenable" command line. Then, press one of the following keys during a game to activate the corresponding cheat function:
Technical demonstration mode
Successfully complete the following modes in order: "Training", "Time Trial", "Gun Shooting", "Survival". Note: Completing each mode will unlock the next mode in the sequence. Then, technical demonstration mode will be unlocked. Use it to watch the CPU demonstrate its best time with the gun.
Infinite ammo
Successfully complete the game without submitting to Ocelot when being tortured to save Meryl. Then at the end of the game you will receive a bandana. Save your game, then start a new game using the same saved game. Now when you equip the bandana you can use an unlimited amount of ammo and will not have to reload your gun.
Stealth camouflage
Successfully complete the game with submitting to Ocelot when being tortured to not save Meryl. Then at the end of the game you will receive stealth camouflage. Save your game, then start a new game using the same saved game. Now when you equip the stealth camouflage enemies (except bosses) and cameras will not detect you.
Camera
Reach area B2 of the tank hanger. Then at the end of the hallway to the right of the door where you fight Ocerot is a secret room that is entered after using C4 explosive. In the room are security card level 4 and 6 doors. The camera is in the room behind the security card level 4 door. Alternatively, beat the game with submitting to Ocelot when being tortured. After you receive the camera there will be an "Album" option on the main menu, use this option to view pictures that have been taken.
New textures
Successfully complete the game two times using the same saved game file, and getting a different ending both times by getting the bandana and stealth camouflage. Then during the next (third) time the game is played, reach Ninja without using the bandana or stealth camouflage. If done correctly, Ninja will be red. There will now be new textures for Snake and Ninja and new bonus music during the ending.
Alternate costume
Successfully complete the game two times using the same saved game file, and getting a different ending both times by getting the bandana and stealth camouflage. Then during the next (third) time the game is played, Snake will change into a tuxedo in the elevator.
Codec frequencies
NameFrequency
Campbell/Naomi140.85
Mel Ling140.96
Master141.80
Otacon141.12
Meryl140.15
Nastasha141.52
Deepthroat140.48
Pantless Meryl
Follow Meryl into the Women's bathroom and reach the last stall in under five seconds. Meryl will be caught with her pants down during the next sequence.
Humorous Meryl comments
Look at Meryl with the scope or camera.
Hidden ghosts
Take a picture of the following locations using the camera to view hidden ghosts who are KCEJ development team members.
NameLocation
FujimuraElevator in the Comm Tower B complex
FukushimaHeliport; looking out to sea from cliff
HiranoElevator in Comm Tower B; deep in the shaft of top level
IshiyamaHeliport top of building
ItoInside elevator to tank hangar
Jerem BlausteinSniper Wolf's corpse
KanedaThe mirror located in the Women's restroom
KimuraMG underground base; tip of Metal Gear 's railgun
KinbaraDark area of stairs
KitaoDecoy Octopus (fake DARPA chief) corpse
KobayashiRock in canyon
KobayashiJohnny Sasaki holding cell, near DARPA chief
KojimaOtacon lab; the picture frame to the right
KorekadoMen's restroom
KozyouBehind the watertank-like structure in the Canyon
KutomeObservation room
MakimuraHidden armory store room; behind the weakened wall
MatsuhanaHallway of corpses; outside Otacons lab
MizutaniWhen fighting Metal Gear
MoriLowest point of elevator; Comm Tower B
MukaideReflection in wolfdog cave puddle
MuraokaWater in cargo dock
NakamuraIn Meryl's blood pool; where she is sniped
NegishiSewage waterfall
NishimuraNext to Baker's corpse
OkajimaMaggots of the real DARPA Chef in cell
OnodaWhere Baker is tied up
SasakiPicture frames in the Commander's room
SatoComm Tower A; roof destroyed by Hind D missiles
Scott DolphDeep down in the dark from the walkway between Comm Towers A and B
ShigenoHeliport,security caera by staircase
ShikamaElectric floor
ShimizuWolf dog cave; first crawling point
ShinkawaDeep in Sniper Wolf's hallway behind the second pillar
SonoyamaTorture machine
TakadeNinja room; glass atedga
TanakaHeliport; sleeping soldier
TougoEnd of boiler room; in Blast Furnace with the steam
ToyotaContainer in the middle of Raven's warehouse
UeharaEdge of elevator; where the ravens are
YamashitaTip of nuke warhead in nuke storage room
YoshimuraDead end of air duct
YoshiokaBridge on the third floor of the blast furnace