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.
First person play mode
Successfully complete the game once on any difficulty setting except for "Very Easy". Then a selection for first person play mode will be unlocked on the "Special" option at the main menu. Then while playing a game, quickly press Triangle(2) after selecting that option to switch the view to first person.
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.
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.
Successfully complete the game two times on any difficulty setting using the same saved game file. Then during the next (third) time the game is played, Snake will have a tuxedo, Meryl will have Snake's original outfit, and Ninja will have a red and blue cyborg costume.
- Alternate title screen
At the title screen, press the D-pad to change the background color
Konami game surprise
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.
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.
Defeating Psycho Mantis
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.
Seeing through Psycho Mantis' eyes
When fighting Psycho Mantis, press Triangle to see through his eyes.
Easier driving scene
To get a better view when shooting at Liquid Snake in the driving scene, hold Triangle while shooting the gun.