If you visit The Cult of Rapture you may well be able to download the official sound track for free. It's been on there a couple of days so I apologise for the lateness, Banks Holiday weekends have a habit of mucking things up.

The score was created by film, television and video game composer Garry Schyman and features a combination of early twentieth century writing, aleatoric elements, musique concrete, traditional tonal and late romantic styles that capture the distinct retro-futuristic aesthetic of the game.