Metal Gear Solid 2: Substance
Beat 50% of Raiden's VR missions.
Beat 100% of Raiden's and Ninja Raiden's VR missions.
Beat 50% of Snake's VR missions.
Beat 100% of Pliskin's VR missions.
Metal Gear Solid 1 Snake:
Beat 100% of Pliskin, Snake, Tuxedo Snake, Ninja Raiden, Raiden X, and Raiden.
Beat Bomb Disposal, Eliminate, and Hold-Up modes.
Beat the game twice and Snake and Raiden will be wearing sunglasses.
European Extreme difficulty:
Beat the game under normal difficulty.
Boss Survival mode and Casting Theater:
Beat Sons Of Liberty under any difficulty setting.
Control Title Screen:
Press White to hear a gunshot and use the Right thumbstick to change the colors.
Dog Tag rewards:
Collect 30 to get the Bandana, Infinite Ammo - Tanker Mission
Collect 80 to get Stealth Invisibility - Tanker Mission
Collect 80 to get Infinite Ammo - Plant Mission
Collect 120 to get the Stealth Invisibility - Plant Mission
Collect 160 to get the Orange Wig, Infinite Grip - Plant Mission
Collect 200 to get the Blue Wig, Infinite Oxygen - Plant Mission
Thanks to Revolution readers Billy, Marcus, The_Volx and Frankiedragon!