There's an entire album's worth of original music, 22 tracks, where a guitarist named Woody Jackson and electronic music group Tangerine Dream composed new music, sent it to Alchemist and Oh No who made beats out of it, then Woody Jackson and Tangerine Dream played more stuff over it, and DJ Shadow mixed the whole thing, and its on Spotify
4. "haha, had no memory of that" In response to Reply # 2
I had the impression from the wikipedia page that DJ Shadow "Mixed" it more in the sense of coming in as an engineer (tweaking EQ/Compression etc) rather than it being any kind of DJ mix...I thought Woody Jackson and tangerine dream played the melodies, and Alc and Oh No were the ones programming drums and chopping loops, but shadow was really 'creating' the music
5. "I'm surprised that more wasn't made of how interesting this game's sound..." In response to Reply # 4
Woody Jackson was primarily the score for Michael, Gangrene for Franklin and Tangerine Dream for Trevor, but during regular playground gameplay with the cops the stems would get mixed together depending on your actions and setting. It was really unique, and especially now that the Tangerine Dream specific tracks are out there on their own it's pretty interesting to consider what the other artists' original work sounds like. The TG tracks feel like the basic inspiration for the whole thing but it'd be interesting to see what the other guys originally made.