More than 20 years after the release of the game, the Metal Gear Solid Original Game Score has been shared online by Metal Gear modding group RedCode Interactive. The track features the music that plays during the cutscenes (‘polygon demoes’, as they are called in the game), composed by Gigi Meroni, and even some tracks that didn’t make it into the final game.
You can download the files here.
The official soundtrack for MGS1 does not contain cutscene and dialogue music, only in-game music and the main theme and end credits, as well as some bonus tracks. The music above has never been officially released.