Adaptive Audio (not just Interactive)

• All the music is streamed, but we were able to still make it somewhat interactive.
• Haunted House Level - Organ music fades in/out depending on how close you are to the organ - it was written to go with the existing music bed regardless of when in the music you happen to go near the organ.
• Maze of illusion - music changes when playfield changes.
• Carnival of the lost - music changes as you pass through various sections of the playfield.

Here is an article about "Adaptive Audio", which exists in some of video games that the music(track) changes depending on actions in the game.
http://www.iasig.org/pubs/features/adaptaudio/adaptiveaudio.shtml

the introduction is long, so you can skip to examples.
and don't forget to read the paragraph about NFS3 (which i think it should contain more details!)