First released in 2005 for PlayStation 2, the Guitar Hero series created a new fervor for music rhythm games. With its unique guitar shaped controllers and soundtrack of popular rock music, Guitar Hero was an instant success. The gameplay is deceptively simple, with an on screen track that has colored circles scrolling towards the player. The player must then press the corresponding colored button on the neck of the guitar controller while moving a secondary bar on the body of the guitar up and down in a strumming motion. Many controllers also allow for a degree of customization to the way the music is played, with a modulation bar called the whammy bar as well as dials that create reverb and other effects. As such, the Guitar Hero series requires a bit more coordination than most other rhythm games, providing a unique challenge. With the release of Guitar Hero World Tour in 2008, the games also supported the use of microphones and drum controllers, in order to better compete with Rock Band, a similar music rhythm game. Since its debut, the Guitar Hero franchise has earned more than $2 billion dollars in sales, with multiple games, expansions, and merchandise. Guitar Hero has even made its way into arcades, with the debut of an arcade version in 2009.