Norihiko Hibino, who had worked on previous Konami games such as Metal Gear: Ghost Babel, was responsible for the in-game music. Gregson-Williams also arranged and re-orchestrated the original 'Metal Gear Solid Main Theme' for use in the game's opening title sequence. The resultant themes then shaped the action sequences in return. To bypass the language barrier and allow the score to be developed before the cutscenes were finalized, Gregson-Williams was sent short phrases or descriptions of the intended action. Flattered by the research put into creating the CD (as some of the tracks were unreleased, and that what tracks he'd worked on for some films were undocumented), he joined the project soon after. A mix CD containing 18 tracks of Gregson-Williams' work was sent to his office. Kojima's choice of composer for Metal Gear Solid 2 was highly publicized in the run-up to the game's release, with him deciding upon Harry Gregson-Williams, a film composer from Hans Zimmer's studio, after watching The Replacement Killers with sound director Kazuki Muraoka.
