Women's Restroom Codec

When you enter the women's restroom to talk to Meryl, stop and call Nastasha and Mei Ling first. Nastasha will be annoyed. But Mei Ling will be absolutely furious at Snake, and will even say she won't let you save.

Contributed by: discoinferno84 

Hallway Cinematography

After you've reached the hallway directly before Otacon's lab, take the time to examine the guards that the Cyborg Ninja just killed. If you crouch down near them, you'll find that every single body will be shown with cinematic camera angles. Some bodies have multiple camera angles to display them close-up, at a distance, or numerous bodies at the same time. Other angles can be seen by leaning against the wall next to the crater at the end of the hallway, as well as leaning against the wall where the hallway turns left. This trick also works with any plot-relevant character who dies and/or injured and is left lying on the ground.

Contributed by: discoinferno84 

Alternate Ketchup Codecs

After you've escaped from the cell, call Otacon. The conversation will be different depending on how well/if you used the ketchup to escape. If you used it successfully, Snake will be in disbelief that it actually worked. If you failed or didn't use the ketchup at all, Snake won't understand what Otacon's idea was, and state that the guard was just careless.

Contributed by: discoinferno84 

Hidden Briefing Tape

Choose the Briefing section from the main menu. After you've watched the first tape, immediately exit from the Briefing section without watching any of the other tapes. This will automatically trigger a hidden tape in which Snake outright refuses the mission, saying he wants to get back to his huskies at Twin Lakes. Campbell will responded with a more hostile tone, and will not-so subtly blackmail Snake into accepting the mission.

Contributed by: discoinferno84 

Title Screen Tricks

When you reach the title screen, push any of the directions on the D-Pad to be able to get different colors for the background graphics.

Contributed by: KasketDarkfyre 

Alternate SOCOM Dialogue

In the first area of the game, do not pick up the SOCOM. Instead, go into the 1st floor vent. Turn left and follow the path all the way to the end. It'll trigger a cutscene in which the guards talk about the status of their supply of SOCOMs, and how the lock on one of the doors is broken.

Contributed by: discoinferno84 

Snake Goes Insane

When Meryl gets shot by Sniper Wolf, don't retreat. Instead, shoot or throw explosives at Meryl as she's bleeding out on the ground. Meryl will weakly demand to know why Snake has betrayed her. This will also trigger multiple codec calls from Campbell and Naomi, who will yell at you to stop. For maximum effect, try shooting Meryl with one bullet at a time. Eventually, a horrified Campbell will proclaim that Snake has gone insane, and Naomi will call Snake a poor excuse of a man.

Contributed by: discoinferno84 

Campbell's Assessment

Campbell will make different comments depending on how quickly you make it up the elevator at the beginning of the game. If you do it quickly, Campbell will say that age hasn't slowed Snake down one bit. But if you take too long, he'll say that Snake must be feeling a little rusty.

Contributed by: discoinferno84 

Raven Codecs

When you're on the cargo elevator on the way down to the Vulcan Raven fight, take the time to kill several of the ravens around you. This will eventually trigger a call from Campbell and Naomi, who will be utterly disgusted by you. Also, an extra line will be added to Vulcan Raven's pre-battle cutscene; he'll yell at you for killing his friends.

Alternatively, you can call Master Miller while on the cargo elevator. Snake will refer to the birds as crows, but Miller will correct him and explain that particular species of raven. This brief lecture will only appear if you call him while on the elevator, but before he calls to warn Snake about Naomi. If done correctly, he'll do the raven lecture first, and then say, "By the way..." and segue into the scripted Naomi conversation all within the same codec call. Also, any references to crows will be changed to ravens from that point forward.

Contributed by: discoinferno84 

Running And Shooting At The Same Time

Pressing both the Square and X Buttons in tandem will allow you to run and shoot at the same time. This makes the Revolver Ocelot fight, the Communications Tower stair sequence, and several other parts of the game much easier.

Contributed by: discoinferno84 

Alternate Ocelot Scene

At the end of his boss fight, Ocelot will normally praise your skills and comment how long it's been since he's had such a good fight. But if you die repeatedly, it'll trigger a different scene. Ocelot will mock your performance and say you're not cut out for war. He'll also have a different reaction to the Cyborg Ninja.

Contributed by: discoinferno84 

Ocelot's Save Warning

If you haven't saved in a long time before the torture sequence begins, Ocelot will actually break the fourth wall to mention it, and extra line will be added to the cutscene. He'll warn you that it'll be game over if you die by torture, and asks, "You really wanna travel down that long road again?"

Contributed by: discoinferno84 

Meryl Kills Snake

If you hit Meryl, she'll hit back and deal a tiny amount of damage. However, it is possible to kill Snake using this method. If you intentionally get Snake's health down to the bare minimum and let Meryl punch him, it'll trigger a Game Over with Mei Ling saying a unique line: "This can't be!"

Contributed by: discoinferno84 

Blast Furnace Crane Skip

When you go through the Blast Furnace, you normally have to walk slowly along a narrow ledge while avoiding a moving crane. But if you have the Nikita or Stinger missiles, you can actually just shoot the crane. The explosions will severely damage it, letting you get past the ledge without any extra effort.

Contributed by: discoinferno84 

Cardboard Box Fast Travel

The Cardboard Boxes have a secret use aside from stealth. When you come across a cargo truck, get into the back, equip a cardboard box, and don't do anything else. This will automatically trigger a cutscene in which a guard will notice the box and deliver you to another location. The destination depends on what's printed on the side of the box. Box A goes to the Heliport, Box B goes to the Nuclear Warhead Storage Building, and Box C goes to the Snowfield. This trick will significantly cut down on the time you need to spend on backtracking.

Contributed by: discoinferno84 

Extra Johnny Scene

Once you escape from the holding cell, deliberately let Johnny see you, but don't attack him. Instead, let him chase you back into the torture room. This will trigger a brief scene in which his stomach gets the better of him yet again, and he runs to the nearby bathroom. You can even taunt him by knocking on the bathroom door while he's in there, and he'll groan in response.

Contributed by: discoinferno84 

Net Yaroze PlayStation

When you're in Otacon's Lab, head to the center area and look closely at the desks. One of them will have a Net Yaroze PlayStation, complete with a DualShock controller.

Contributed by: discoinferno84 

Alternate Meryl Introduction

There's an alternate scene of Snake and Meryl talking for the first time. If you haven't gotten the SOCOM by this point, Snake will grab the tip of Meryl's FAMAS instead of drawing the gun.

Contributed by: discoinferno84 

Exhausted Snake

After you've finished the stairs sequence and made it onto the roof of the Communications Tower, immediately call Colonel Campbell before the next cutscene. This will trigger a unique Codec. Snake will be out of breath after climbing all those stairs. Naomi will mention that Snake's vital stats indicate he's exhausted. Campbell will jokingly ask Snake if he's out of shape from all the dog mushing he's done since retiring.

Contributed by: discoinferno84 

Controlling Guards on Controller 2 During Escape Route

During the escape sequence, if you plug in a controller into port 2, you can control some of the guards.

Contributed by: retroboy1827 

Hideo Kojima Message (JP Version Only)

If you have a save game of Policenauts on your memory card when you fight Psycho Mantis, he will mention it as usual. However, if you have a save game of Policenauts and Snatcher, you will get a special message saying that you enjoy Hideo Kojima games. After this, Hideo Kojima himself will thank you for your support. Note that this only works on the Japanese version of the game.

Contributed by: rob29 

Get Mei Ling Mad

Keep calling Mei Ling on the codec. Say do not save about 5 to 8 times. She will get mad eventually and stop talking to you.

Contributed by: danyates 

Castlevania Message

If you have a save game of Castlevania: Symphony of the Night on your memory card, Psycho Mantis will give you surprising message before you fight him.

Contributed by: LaC2 

Defeat Psycho Mantis with ease

Make the boss fight with Psycho Mantis much easier by switching your controller to port 2 when the message HIDEO appears on your screen. If you do it correctly, Psycho Mantis will be unable to read your thoughts making the fight much easier.

Contributed by: metalgearsolid5 

A more useful cardboard box

When you're in the cave area with Meryl, hit her and quickly equip a cardboard box. She'll order a wolf to attack you, but if you're in a box, a wolf will pee on it instead. Now whenever that box is equipped the wolves will no longer attack you.

Contributed by: Dinob0t 

Easily cross minefields.

If you don't have the mine detector, but want to cross a minefield without having to worry about blowing up, just go up to the area where you believe mines are and crawl across the ground. Not only will you be unharmed, but you will also receive any claymore mines that you crawl over!

Contributed by: Felix_Arabia_ 

Suikoden Message

If you have a Suikoden Save Game on your Memory Card ,
Psycho Mantis will give you special message regarding Suikoden when he reads your mind.

Contributed by: ShinWesker 

Otacon's Ending

To view Otacon's Ending instead of Meryl's ending after completing the game, submit to Ocelot's torture after being captured.

Contributed by: UltimaterializerX 

Save message from Psycho Mantis

If you save enough times before fighting Psycho Mantis he will tell you how wise you are for saving often.

Contributed by: djmikso 

Alternate Save Message from Psycho Mantis

If you save less than three times before you fight Psycho Mantis, you will get a special message on how reckless you are.

Contributed by: MrFoxhound 

Tokimemo Message (JP Version Only)

If you have at least two Tokimeki Memorial save games on your memory card, Psycho Mantis will comment on it when you encounter him. Note that this includes all PS1 Tokimeki Memorial games made 1998 and earlier. Also, this is exclusive to the Japanese version of the game.

Contributed by: discoinferno84 

Faster elevator

Ever wanted to eliminate the risk of getting caught waiting for the elevator? Just go over to the call button an push it a second time, it will show up immediately. It's quite useful for speedruns!

Contributed by: NitroPalm 

Konami Game Preferences Messages (JP Version Only)

The classic Psycho Mantis memory card easter egg is far more extensive in the original Japanese version. Aside from specific games, he will mention the genres and studios you like based on different combinations of game saves from various titles. If you have at least two saves including Policenauts and the Tokimeki Memorial Drama Series Vol. 1 or 2, he'll comment that you like KCE Japan games. If Snatcher is included among those saves, he'll comment that you like Adventure games. If you have at least two saves including Mitsumete Knight and Tokimeki Memorial: Forever With You or Private Collection, he'll comment that you like dating sims. If you have at least two saves from Jikkyou Oshaberi Parodius, Gradius Gaiden, Susume or Tokimeki Memorial Taisen Puzzle Dama, he'll comment that you like Arcade games. If you have at least three saves from any of the aforementioned games, any of the TwinBee or Tokimeki Memorial games made in 1998 or earlier, or Lightning Legend, he'll comment that you like Konami games.

Contributed by: discoinferno84 

Meryl's Ending

Resist Ocelet's torture to see a happy ending where everyone lives.

Contributed by: MrFoxhound 

Game Preference Messages

Aside from the specific games Psycho Mantis can mention when you encounter him, there are a couple of extra messages that will appear if you have saves from several games on one memory card. He'll mention that you enjoy RPGs if you have a combination of at least two of these games: Suikoden, Azure Dreams, and Vandal Hearts. He'll mention that you enjoy Konami games if you have at least three games saved. These include the aforementioned ones, as well as Castlevania: Symphony of the Night.

Contributed by: discoinferno84 

Azure Dreams Message

If you have a save game of Azure Dreams on your memory card when you fight Psycho Mantis, he'll mention it when you encounter him.

Contributed by: discoinferno84 

Meryl Undressed

There are two different ways you can see Meryl without her pants on. When you're in the vents on the way to the DARPA chief, look down into Meryl's cell and watch her work out. Leave the vent, go back in, and watch her work out. Repeat this five or six times, and eventually she do the workout while undressed.

The second way is when you have to find Meryl when she's pretending to be one of the soldiers. When she runs to the restroom, get to the last stall within five seconds. The cutscene will play out like normal, but she won't be wearing pants because she didn't have enough time to change.

Contributed by: discoinferno84 

How to make the Ninja free you

After you are tortured, thrown in the cell, and called Otacon, the guard goes to the bathroom. Otacon comes, gives you a few things and then when he leaves and the guard comes back, let the guard go to the bathroom 2 more times. When the guard goes to the bathroom the second time, you'll hear something like a FAMAS. The Ninja comes and frees you!

Contributed by: Pin_Cheater 

Ghost Picture of Hideo Kojima

After you beat the Ninja, take your camera and take a picture of the picture of the big orange-like robots in Otacon's lab. When you've done it, reset and load the picture. You'll see a ghost picture of Hideo Kojima!

Contributed by: Pin_Cheater 

Mono TV

Before the fight with the Hind D, change the audio settings from stereo to mono. During the fight, call Campbell twice. At first, he'll advise you to listen for the Hind D's rotors to know which direction it's coming from. However, he and the rest of the team be surprised when they discover you're using a mono TV.

Contributed by: discoinferno84 

Blushing Meryl

When you're with Meryl, stare directly at her in first person view for a minute or so. She'll get embarrassed and blush. The longer you do it, the brighter red her character model will become.

Contributed by: discoinferno84 

Misc. Unlockables

Contributed by: chrono3000, Melchior, DARKCLOUDSTRIFE, _JesusFreak1990, metalgearsolid5, Rage012 

Different ending/music

Contributed by: Warhawk 

Staff on the Codec

Go to a jammed area like the place where you fight Ocelot and set your codec to 140.7

Contributed by: mkwong98 

Demo Theater Mode

Beat the game with either Meryl or Otacon ending to unlock this option. Plays all the Cutscenes and Codec calls threw the whole game depending on what ending you picked.

Contributed by: godreault 

Stealth Camo:

Do submit to Ocelot Torture and you will get the Otacon Ending after you beat the game. When you load up the save file you will now have a “Stealth Camo” in your inventory. When the Stealth Camo is equipped, you will now be Invisible to the soldiers. (Except the Bosses, they will be able to see you)

Contributed by: godreault 

Infinite Ammo:

Do not submit to Ocelot Torture and you will get the Meryl Ending after you beat the game. When you load up the save file you will now have a “Bandanna” in your inventory. When the Bandanna is equipped, you will now have Infinite Ammo.

Contributed by: godreault 

Easier ninja

While fighting the ninja throw a chaff grenade and he will freeze letting you hit him.Once you hit him he will fall to his knees and won't get up until all the yellow dust from the chaff grenade has fallen.

Contributed by: Ecstacy2003 

Animal rights

Shooting crows and rats will make roy and naomi upset. They'll contact you through your codec and tell you how mean you are.

Contributed by: Ecstacy2003 

Tuxedo Costume

Complete the game and save it after the credits end. Load the game and complete it again. Save the game after the credits end. Load the game once more and begin playing. Snake will change into a tuxedo in the elevator during the game.

Contributed by: XPLICIT187 

All Weapons

start the game with msg.exe -cheatenable in the command line. Then in game use the following codes:

Contributed by: ECFan89 

Cheat Codes

Start the game with mgsi.exe -cheatenable in the command line. Then press the following keys during the game:

Contributed by: Starky27 

Alternate Title Screen

Complete 85% of the game to unlock Ninja Mode and the title screen will change to show the face of the Ninja.

Contributed by: robertwarnes91 

Misc. Unlockables

Contributed by: KasketDarkfyre, Ben del Raichu, eelshock61, Mr Flunchy, rob29