Metal Gear Solid 2: Substance Cheats

Control title screen
Press White to hear a gunshot and see a flash at the title screen. Use the Right Analog-stick at the title screen to change the background color.

Control Codec sequences
Press the Left Analog-stick or Right Analog-stick to move the faces. Click the Left Analog-stick or Right Analog-stick to zoom in. When using your Codec to contact Otacon or others in the game, press R to reveal Snake's or Raiden's thoughts about those persons, with some funny phrases. You will also hear who they really feel about their women.

Stealth, Bandanna and Wig bonuses
Complete the following goals to get the Stealth (invisibility), Bandanna (unlimited ammo for Snake), and the Wig (unlimited ammunition for Raiden). To get Stealth and Bandanna, complete the Tanker mission three times on three different difficulty settings (all on the same saved file) and get all the dog tags. To get Stealth and Wig, complete the plant three times on three different difficulty settings (all on the same save file) and get all the dog tags.

Sunglasses
After completing the game two times, Snake and Raiden will be wearing sunglasses.

Alternate Ending
Clear "A Snake Tale" to unlock the M9. Then use it to stun all the Bosses instead of killing them to view an alternate ending.

Unlock Items & Characters
Blue wig (Infinite Oxygen): Get at least 200 dog tags on plant mission and beat the game.
Brown wig (Infinite Ammo): Get at least 70 dog tags in plant misson and beat the game.
Orange wig (Infinite Grip): Get at least 160 dog tags on plant mission and beat the game.
Stealth camo. (Invisibility): Get at least 110 dog tags in plant mission and beat the game.
Unlock Bandana (Infinite Ammo for Tanker Chapter): Get a total of 50 dog tags in the Tanker Chapter and finish the chapter. After viewing your Clear Code you will obtain the Bandana. Save, and then load your save data to start a new game with the Bandana in your inventory.
Unlock Stealth for Tanker stage: Get a total of 80 dog tags in Tanker stage, and Stealth will be unlocked for Tanker stage.
Unlock the Digital Camera for Tanker-Plant : beat the game (Tanker-Plant) on any difficulty level.
USP Suppresser: Beat the game and then save. Start a new game with the saved info. Go to the Navigation Deck after you defeat Olga. Go to the place where you recieve the Thermal Goggles and you should find this weapon on the middle platform.
Iroquois Pliskin: Complete 50% of the VR Training missions with Snake to play as this character in VR mode.
MGS1 Snake: Complete 100% Tuxedo Snake in VR and MGS1 Snake will be unlocked.
Naked Raiden: Complete 100% of Raiden's (Ninja) VR Missions.
Ninja Raiden: Complete 50% of the VR Missions with Raiden.
Raiden X: Complete all of the VR missions while playing as Raiden.
Tuxedo Snake: Complete 100% of Pliskin's Missions In VR Mode.

Unlock Modes
Boss Survival: Finish both the Plant and Tanker Missions on any difficulty. This works playing the Tanker and Plant seperately or playing the Tanker/Plant as one game.
Casting Theater: Finish both the Plant and Tanker Missions on any difficulty. This works playing the Tanker and Plant seperately or playing the Tanker/Plant as one game.
Extreme and European Extreme difficulty modes: Complete the game once.
Photograph Mode (Snake VR Missions): Complete all of the levels in Bomb Disposal Mode, Eliminate Mode and Hold Up Mode (Alternative Missions) to unlock Photograph Mode.

Unlock Stuff With Document Save
If you have a save from Document of Metal Gear Solid 2 on your memory card, more goodies will be unlocked for Substance right off the bat.

Bugs in Rations
In some portions of the game you'll see little sea mites on the floor. If you have to crawl through the mites they'll sometimes get on your character, and start eating your rations. If you leave them there long enough you'll lose rations--to get rid of them, open your item select menu and quickly cycle through it, going back and forth past the rations. The sea mite will be "shaken" off, saving your food.