In TTS, both are at maximum from the beginning (as in MGS2). In an interview, Dennis Dyack commented that VR training was to be included, but time ran out before the feature could be implemented * In the PlayStation version of MGS, the player's life and maximum ammunition are gradually increased as the game progresses. Melee, Super Mario Sunshine, The Legend of Zelda: The Wind Waker, and Eternal Darkness: Sanity's Requiem * The entire musical score with the exception of The Best Is Yet To Come was rewritten * Like MGS2, the pause screen has a map of the base, the original version just had the name of the area Snake was in * The Game Over screen was replaced * The Very Easy difficulty setting was added * No VR Missions were included. * Guards can now call for backup and make regular reports on patrols * Boss Survival mode was added to the Special menu * Psycho Mantis' dialog regarding saved games was altered to mention GameCube games, specifically Super Smash Bros. However, unlike MGS2, there is no reward for doing so. The PlayStation version's disk swap occurred before entering the Blast Furnace * Like MGS2, dog tags can be collected from enemies. These dialog changes were more closely related to the original Japanese text and then implemented in the reminiscing sequences of the Shadow Moses level in Metal Gear Solid 4 * Many features from MGS2 were implemented, including First Person Aiming and the hanging feature * All cutscenes were re-rendered, most undergoing major reworking under guest director Kitamura, including controversial changes such as Solid Snake springboarding off a missile that Liquid fires from his Hind D, launching him into the air where he fires the coup de grace at Liquid * The ending text was rewritten to reflect the year 2003, as opposed to 1998 when the original was released * The disk change location is now at the bottom of Communications Tower A. * Minor dialog changes were made to some bits of dialog.
From the Metal Gear wiki: Apart from the obvious upgrade in graphics, The Twin Snakes has a number of less apparent alterations compared to the PlayStation version.