Metal Gear Solid/Unlockables

Metal Gear Solid: The Twin Snakes
These can be unlocked on any difficulty.
 * Alternate ending theme: Complete the game three times.
 * Bandana: Beat the game with Meryl's ending (beat the torture scene).
 * Boss Survival Mode: Beat the game once.
 * Crimson Ninja: Beat the game twice.
 * Meryl Demo: Complete the game once with Meryl's ending.
 * Meryl Demo 2: Beat the game once as Tuxedo Snake while saving Meryl.
 * Ninja save icon: Beat the game twice.
 * Otacon Demo: Complete the game once with Otacon's ending (submitting into the torture).
 * Otacon Demo 2: Beat the game once as Tuxedo Snake while saving Otacon.
 * Sneaking Suit Meryl: Beat the game twice.
 * Start with Camera: Obtain the Camera and beat the game.
 * Stealth: Beat the game with Otacon's ending (submit to the torture).
 * Tuxedo Snake: Beat the game two times.

Tips

 * Things to be merged into walkthrough
 * Beat Psycho Mantis: in the Psycho Mantis boss fight, if you switch your controller from port 1 to port 4, he will be unable to read your mind and dodge your bullets.
 * Easy Health Upgrade: when fighting the Ninja in the computer room, go to the top right corner of the room and shoot Mario on top of the computer to replenish your health.