ソニックアドベンチャー
Development began soon after the American release of "Sonic Adventure" in 1999 and lasted 18 months. The game was produced in commemoration of the "Sonic" series' tenth anniversary and was designed to be faster-paced and more action-oriented than the original. The development team also expanded upon the presence of the Chao creatures and other player characters. Its locations were influenced by American locations such as San Francisco and Yosemite National Park. Sega announced "Sonic Adventure 2" in October 1999 and exhibited it at E3 2000. It was released in North America on June 19, 2001, and in Japan and Europe on June 23, 2001. An enhanced port for the GameCube, Sonic Adventure 2: Battle, was released late 2001 in Japan and early 2002 in North America and Europe with improved textures and multiplayer options. Together, the Dreamcast and GameCube sold more than copies worldwide. "Sonic Adventure 2" was also released as a download for PlayStation 3, Xbox 360, and Windows in 2012, with Battle as Downloadable Content.