"That trailer was cut quite closely to the music we used, Claude Debussy's Prélude no. 12, and when we put it online, lots of people commented that they liked the "reactive music", even though the piece of music wasn't reactive at all. It's music that is over a hundred years old and we just let it play normally. But there was something about the music, the way that it stopped and started in interesting ways, that made lots of people who saw the trailer think we were doing something clever."