Title Screen Colors ... In the Japanese version of the game, at the title screen press up down left or up down right. This will allow you to change through different background colors. (Japanese version Only)
Extra Modes ... The extra modes come out of VR Training. In the beginning you are only allowed to use practice mode, if you beat all 10 of the practice stages then you get Time Attack, which is a little more difficult because you get a time limit to complete the level. If you beat all 10 of the Time Attack stages then you will get Gun Shooting mode, where you have to kill all of the guards in the time limit that they give you. You only get a Socom with a suppresser and about 5 bullets for every guard.... you also aren't allowed to be spotted, you must kill them without the other guards seeing you. If you run outta bullets then you shall have to choke them. If you complete those 10 stages then you shall have Survival Mode. You have to go from one stage to another with a time limit for all of them(which is 7 mins for all of the stages). You only start with 30 bullets but, if you kill a guard then they give you some more bullets. Survival is the last mode and is very difficult.
See Ghost ... In order to see ghost you must get the camera. There are 2 ways you can get the camera. One way is to beat the game with the ending of Meryl dies and starting a new save file with the camera already on the inventory.
Another way is by beating Liquid Snake in the Helicopter sequence and the going to Base 1, floor B-2 with the Level 7 Card where there are 2 guns and you will need to have C-4 to blow up the wall to the bottom-right where you fought Revolver Ocelot. The camera is inside one of the 2 rooms. Also... sometimes you may run into a jammed door, try using C-4 and then opening the door. When you have the camera, in order to see the Ghost then you should have 2 blocks of free memory if you want to save the picture. Take pictures of different things and you may see one of the programmers or artist. You can get some pictures by taking pictures of ravens.
Tuxedo Snake ... In order to get tuxedo Snake you must beat the game 2 times and then start the game and Snake shall be in a tuxedo.
Stealth Suit ... If you beat the game with the ending where Meryl dies then they shall give you the stealth suit. It allows the guards to not be able to see you.
Bandanna ... If you beat the game with the ending where Meryl lives then you will get the Bandanna. If you have this then you shall never run out of bullets.
Konami Secret ... A rumor over the net on other Metal Gear Solid pages says that if you have other Konami files saved on your memory card then when you battle Psyco Mantis then something will happen... It appears that Psyco Mantis will not be able to read your mind if you have the controller plugged into the 2nd player slot while fighting him. He will read your memory card when he says "I'm looking into your soul." If you have Castlevania saved on the memory card, he'll say "You like Castlevania."