Successfully complete the game once to unlock a first person play mode option.
Successfully complete the game without submitting 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.
Successfully complete the game with submitting 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.
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 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.
Successfully complete the game two times using the same saved game, and getting a different ending both times by getting the bandana and stealth camouflage. Then, next (third) time 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.
Successfully complete the game two times using the same saved game, and getting a different ending both times by getting the bandana and stealth camouflage. Then, Snake will change into a tuxedo in the elevator during the next (third) time the game is played.
At the title screen, press the D-pad to change the background color.
Play the game using a memory card that contains a saved game from any prior Konami title (Castlevania, ISS Soccer, Silent Hill, Suikoden, etc.). Then when Psycho Mantis attempts to read your character's mind, he will mention various game titles.
| Name | Frequency |
| Campbell/Naomi | 140.85 |
| Mel Ling | 140.96 |
| Master | 141.80 |
| Otacon | 141.12 |
| Meryl | 140.15 |
| Nastasha | 141.52 |
| Deepthroat | 140.48 |
Equip a box while in the trucks to travel to the destination on the boxes.
Snipe the rats above where you first encounter Wolf or Snipe the ravens when at your second encounter with Raven.
Plug the controller into port two and press any button before fighting Psycho Mantis. The word "Hideo" will appear in the corner of a black screen. Use controller two to fight against Mantis to keep him from knowing your moves.
When fighting Psycho Mantis, press Triangle to see through his eyes.
To get a better view when shooting at Liquid Snake in the driving scene, hold Triangle while shooting the gun. -From: avidgamr@blueriver.net
Take a picture of the following locations using the camera to view hidden ghosts who are KCEJ development team members.
| Name | Location |
| Fujimura | Elevator in the Comm Tower B complex |
| Fukushima | Heliport; looking out to sea from cliff |
| Hirano | Elevator in Comm Tower B; deep in the shaft of top level |
| Ishiyama | Heliport top of building |
| Ito | Inside elevator to tank hangar |
| Jerem Blaustein | Sniper Wolf's corpse |
| Kaneda | The mirror located in the Women's restroom |
| Kimura | MG underground base; tip of Metal Gear 's railgun |
| Kinbara | Dark area of stairs |
| Kitao | Decoy Octopus (fake DARPA chief) corpse |
| Kobayashi | Rock in canyon |
| Kobayashi | Johnny Sasaki holding cell, near DARPA chief |
| Kojima | Otacon lab; the picture frame to the right |
| Korekado | Men's restroom |
| Kozyou | Behind the watertank-like structure in the Canyon |
| Kutome | Observation room |
| Makimura | Hidden armory store room; behind the weakened wall |
| Matsuhana | Hallway of corpses; outside Otacons lab |
| Mizutani | When fighting Metal Gear |
| Mori | Lowest point of elevator; Comm Tower B |
| Mukaide | Reflection in wolfdog cave puddle |
| Muraoka | Water in cargo dock |
| Nakamura | In Meryl's blood pool; where she is sniped |
| Negishi | Sewage waterfall |
| Nishimura | Next to Baker's corpse |
| Okajima | Maggots of the real DARPA Chef in cell |
| Onoda | Where Baker is tied up |
| Sasaki | Picture frames in the Commander's room |
| Sato | Comm Tower A; roof destroyed by Hind D missiles |
| Scott Dolph | Deep down in the dark from the walkway between Comm Towers A and B |
| Shigeno | Heliport,security caera by staircase |
| Shikama | Electric floor |
| Shimizu | Wolf dog cave; first crawling point |
| Shinkawa | Deep in Sniper Wolf's hallway behind the second pillar |
| Sonoyama | Torture machine |
| Takade | Ninja room; glass atedga |
| Tanaka | Heliport; sleeping soldier |
| Tougo | End of boiler room; in Blast Furnace with the steam |
| Toyota | Container in the middle of Raven's warehouse |
| Uehara | Edge of elevator; where the ravens are |
| Yamashita | Tip of nuke warhead in nuke storage room |
| Yoshimura | Dead end of air duct |
| Yoshioka | Bridge on the third floor of the blast furnace |
| Enable Code For Disc 1 & 2 (Must Be On) | D00C3AB6 1000 800C3AB6 1040 D00C492A 1040 800C492A 1000 |
| Enable Code For VR Disc (Must Be On) | D00C209A 1040 800C209A 1000 |
| Infinite Health | 800B4DAE 0600 800B4DB0 0600 |
| Infinite Oxygen (Press R1) | D00AB950 0008 800ABA34 03E7 |
| Radar Not Jammed When Spotted | 800ABA00 0000 |
| Ghost Mode | D00B4DB8 0000 800ABA10 0000 |
| Auto Reload | 800AB9EC 001E 800ABA04 001E |
| Never Have Time Bomb | 800B4E06 0000 |
| Have 99 Rations | 800B4DFC 0063 800B4E12 0063 |
| Have 99 Medicine | 800B4DFE 0063 800B4E14 0063 |
| Have 99 Diazepam | 800B4E00 0063 800B4E16 0063 |
| Have SOCOM Pistol | 800B4DBA 03E7 800B4DCE 03E7 |
| Have FAMAS Rifle | 800B4DBC 03E7 800B4DD0 03E7 |
| Have Nikita | 800B4DC0 03E7 800B4DD4 03E7 |
| Have Stinger | 800B4DC2 03E7 800B4DD6 03E7 |
| Have PSG1 Rifle | 800B4DCC 03E7 800B4DE0 03E7 |
| Have Claymore Mines | 800B4DC4 03E7 800B4DD8 03E7 |
| Have C4 | 800B4DC6 03E7 800B4DDA 03E7 |
| Have Grenades | 800B4DBE 03E7 800B4DD2 03E7 |
| Have Stun Grenades | 800B4DC8 03E7 800B4DDC 03E7 |
| Have Chaff Grenades | 800B4DCA 03E7 800B4DDE 03E7 |
| Have Cigarettes | 800B4DE2 0001 |
| Have Scope | 800B4DE4 0001 |
| Have Cardboard Box A | 800B4DE6 0001 |
| Have Cardboard Box B | 800B4DE8 0001 |
| Have Cardboard Box C | 800B4DEA 0001 |
| Have Night Vision Goggles | 800B4DEC 0001 |
| Have Thermal Goggles | 800B4DEE 0001 |
| Have Gas Mask | 800B4DF0 0001 |
| Have Body Armor | 800B4DF2 0001 |
| Have Ketchup | 800B4DF4 0001 |
| Have Stealth Camouflage | 800B4DF6 0001 |
| Have Bandana | 800B4DF8 0001 |
| Have Camera | 800B4DFA 0001 |
| Have Level 7 Key Card | 800B4E04 0007 |
| Have Mine Detector | 800B4E08 0001 |
| Have MO Disc | 800B4E0A 0001 |
| Have Rope | 800B4E0C 0001 |
| Have Scarf | 800B4E0E 0001 |