Hans Zimmer has composed more than 100 films, everything from The Dark Knight and Batman Begins to The Lion King, and now he’s the music man behind the blockbuster video game, Call of Duty: Modern Warfare 2.

GCD: What’s the most obvious difference between scoring a video game, like Call of Duty: Modern Warfare 2 versus a feature film?
Zimmer: When I score a movie, I know who my main protagonist is. I know who is moving at what rate and whether he's gonna go and do something. When I'm scoring a video game, since really I'm writing the music from the perspective of the player, I never know if he's good enough to get to the next bit in time, or if I just have to hang out and try to figure out how to pedal around with time.

GCD: Video game music can get pretty repetitive and even get on your nerves a bit. Was this something you were aware of and tried to address?
Zimmer: I was aware and I’m trying to figure out ways of getting around this. Look, you've gotta start somewhere, so you might as well start on the most successful game of all time and then go “OK, we could do a lot better next time we do something.”

GCD: How did you approach The Dark Knight after having done Batman Begins?
Zimmer: The main character was the Joker, so I was trying to figure out what is anarchy and how can you represent that differently. And so I thought “What if I try to do everything within one note?” He is so constant but he's like a tightly wound wire. You don't know when it's going to snap and when it's going to go nasty on you. So I never wanted the audience to know how far that note would go. Usually for the bad guy, you just throw a lot of drums at it. But actually it's much more like some evil whisper and you have to lean in a little bit to hear what the note was saying to you.

Click here to find out which villain Zimmer wants to see in the next Batman movie.