Agents—and a sequel in Japan. Also in 2005, Harmonix and the small publisher RedOctane released Guitar Hero, a game inspired by Bemani's GuitarFreaks. However, instead of the Japanese pop that comprises the earlier title's soundtrack, Guitar Hero features Western rock music. The game reinvigorated the rhythm genre, which had stagnated because of a flood of Dance Dance Revolution sequels and imitations.2008. "Best Rhythm Game: Rock Band 2" . UGO. Retrieved 2009-04-29. Guitar Hero spawned several sequels, and the franchise overall earned more than $1 billion, with the third installment ranking as the best selling game in North America in 2007. Harmonix followed Guitar Hero with the Rock Band franchise, which also earned over $1 billion. Rock Band titles support multiple instrument controllers and cooperative multiplayer, allowing players to play as a full band. The Guitar Hero franchise followed suit with the band-oriented, Neversoft-developed Guitar Hero World Tour. Guitar Hero installments based on specific bands, such as Metallica and Aerosmith, were also published. Additional songs for Guitar Hero and Rock Band were made available for purchase via the Internet, which generated further revenue. Artists whose work is featured in the games receive royalties, and the increased publicity in turn generates further sales of their music. The success of the Guitar Hero and Rock Band franchises widened the console video game market and its demographics, and the popularity of the genre drove increased sales of consoles. In 2008, it was reported that music games had become the second most popular video game genre (behind action) in the United States, with 53% of players being female. At its height in 2008, music games represented about 18% of the video game market. Video game industry analysts considered 2009 to be a critical year for rhythm games, and they believed that it would allow them to gauge the future success of the genre. Both the Guitar Hero and Rock Band franchises were expanded, and they received entries for handheld gaming devices and mobile phones. Specialized titles that targeted specific genres and demographics, such as Band Hero for pop music and Lego Rock Band for younger players, were released. Sales of music games were down in the first half of the year. This decline was attributed to fewer purchases of instrument controllers; it was assumed that players had already bought such controllers and were reusing them. While analysts had expected that United States sales of Guitar