Playing games

You're running through a ruined city, weapon at the ready. A monstrous enemy could be lurking around every corner. Your colleagues are shouting orders. Your mission: To save the city from an alien invasion. That's the premise of most shoot 'em up video games.

As players move through the computer-generated scenery, the sights, sounds and even smells of the animated fantasy world become ever more real. You feel like you're in the middle of an action movie - a sensation made all the more intense through music.

Sensory fantasy worlds

As the suspense reaches breaking-point, the music wobbles ominously in the background. During the fight scenes, the sound explodes like a hand grenade or a machine gun. Then, when it's all over, the tempo slows down to emphasize the prevailing sense of calm. Music transports players through different emotions and moods, underscoring the events on screen.

Borislav Slavov is a musician, computer scientist and video game fanatic. He specializes in composing music for computer games and produced the music for the "Crysis" series - an end-of-the-world shooter game with impressive graphics and a large helping of blood and gore.

It's the games with these sorts of dynamics which excite Borislav, who goes by Bobby, the most. "The biggest challenge is producing music that fits 100 percent to every moment in the game," he said. "In action games, for example, the music has to fit no matter if I pull out the biggest weapon and slay everyone or I strategically maneuver myself through the scenery."

Car racing games are much easier, he said, grinning, "They just move forward!"

Super quick reactions

Techniques for adding music to computer games vary. Melody, harmonies, dynamic elements, key changes, volume and tempo can all be played with. The composer doesn't know how quickly a player will complete a particular operation.

If a player spends 10 minutes creeping through the computer-generated bushes, the music has to fit for the duration. That's why Bobby Slavovo uses small filler pieces which can be fitted to the bare bones of the musical score, forming a sort of blanket background sound.

It's common to hear radio presenters speaking while music is playing in the background, and each segment is often divided by jingles. The jingles are played on the push of a button, but despite that, the music still sounds like it is one continuous piece.

Video games also employ this technique - only at a much faster pace. "Film scores are linear. As a composer, you know the journey from the first to the last frame. All you need to do is follow the film's atmosphere," he explained. "But with video games, you've got no idea what will happen next. It's all down to the player's decisions and actions."

Hollywoodheavyweights

It wasn't long before the genre came to the attention of famous film score composers. And just like major blockbuster movies, some videogames now also come with an OST, or original soundtrack, with the obligatory theme song or title track.

The makers of "Crysis 2" managed to snap up Hollywood composer Hans Zimmer. He's best-known for his scores accompanying films such as "Pirates of the Caribbean," "The Dark Knight" and "The Da Vinci Code." The Oscar-, Golden Globe-, and Grammy-winning composer was happy to work on the project when the makers asked him.

It wasn't the first time that Zimmer has composed for a computer game. He'd already provided the music for '"Call of Duty: Modern Warfare 2." For "Crysis 2," Hans Zimmer wrote the theme tune and Bobby Slavov, together with his colleague Tilman Sillescu, composed the rest around it. All of the game's music was recorded by the London Symphony Orchestra.

Synthesizers were only used sparingly so that the music would sound as authentic as possible.

Award-winning music

Video game music is now a highly regarded genre. In 2011, composer Christopher Tin won two Grammys for the soundtrack to a video game. The song "Baba Yetu" is the title track from the strategy game "Civilization IV," which includes orchestral music and the sounds of the Soweto Gospel Choir.

Tin not only wrote the title track, but also produced the entire musical arrangement for the game, netting himself a Grammy in the process. As yet, there's no special category for video game music, despite the fact that Grammys are increasingly being awarded to music from the genre.

Right now, Hollywood composers are battling it out to be chosen to produce the music for big blockbuster games. Oscar winner Trent Reznor of the US industrial rock band Nine Inch Nails (who has also written music for films like "The Social Network" and "The Girls with the Dragon Tattoo"), has been writing videogame music since 1996. He most recently worked on "Call of Duty: Black Ops II" - one of the biggest computer games of all time.

The combat game "Medal of Honor" was given musical support by the Oscar-winning composer Michael Giacchino. He had previous experience creating the music for "The Lost World" (1997), the first video game to with an entirely orchestral soundtrack. Back then, it was a sensation when you think that the history of video game music spans just two decades.


New musical dimensions

The genre continues to develop. At the moment, Bobby Slavov is working on the soundtrack for his next blockbuster. But things are different this time: The music is much more subtle than before, switching key, tempo and volume in seconds. He plays the music together with short sequence from a video game. The alternations in the music don't sound too hectic at all, rather, as if they were written especially for each scene.

"I'm not afraid to try new things," said Slavov. "It's fun continually reinventing myself." A passion he's clearly adopted from his idol Hans Zimmer.