http://uk.music.ign.com/articles/741/741211p1.html
These stress cues are extremely static. Aside from random effects throughout (percussion, small string builds, vocals, etc.) the primary layers are totally steady and non-dynamic. The reasoning for this is that they can be made dynamic in the game. If there are 15 instruments in the stress cue, they can all be treated independently and rise / fall as Sam approaches and engages danger. So if it's a steady orchestra line or percussion element, it can rise as Sam comes up behind an enemy and continue to build right up to the point of engagement. When I saw this work in the game for the first time I was blown away, especially by the interaction between 'stress' builds and the calmer infiltration underneath.
The last main challenge was the cinematics. As I was saying before, many of the Xbox 360 cinematics are interactive. Basically you come into the scene with a synced cue - scored direct to picture - then you move to a loop-able part, then back to image sync, then to loop, then to ending. All the endings and loops have to be dynamic, meaning the player chooses when he moves to the next step, so the music has to be written to allow changes at any time. This was probably the hardest thing I've ever done musically - in comparison it makes scoring a film a walk in the park!
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The last main challenge was the cinematics. As I was saying before, many of the Xbox 360 cinematics are interactive. Basically you come into the scene with a synced cue - scored direct to picture - then you move to a loop-able part, then back to image sync, then to loop, then to ending. All the endings and loops have to be dynamic, meaning the player chooses when he moves to the next step, so the music has to be written to allow changes at any time. This was probably the hardest thing I've ever done musically - in comparison it makes scoring a film a walk in the park!