Open Your Heart (Sonic Adventure)

Sonic Adventure
European Dreamcast cover art
Developer(s)	Sonic Team USA
Publisher(s)	Sega
Director(s)	Takashi Iizuka
Producer(s)	Yuji Naka
Programmer(s)	Tetsu Katano
Artist(s)	Kazuyuki Hoshino Yuji Uekawa
Writer(s)	Akinori Nishiyama
Composer(s)	Jun Senoue Fumie Kumatani Kenichi Tokoi Masaru Setsumaru
Series	Sonic the Hedgehog
Platform(s)	Dreamcast, GameCube, Microsoft Windows
Release	Dreamcast JP: December 23, 1998 NA: September 9, 1999 EU: October 14, 1999 AU: December 3, 1999 GameCube NA: June 17, 2003 JP: June 19, 2003 AU: June 20, 2003 EU: June 27, 2003 Microsoft Windows JP: December 18, 2003 EU: February 6, 2004 AU: February 6, 2004 NA: September 14, 2004
Genre(s)	Platformer, action-adventure
Mode(s)	Single-player, multiplayer

Sonic Adventure is a platform video game developed by Sonic Team and published by Sega. It was originally released for the Dreamcast as a launch title in Japan in 1998, and worldwide the following year. It was the first game in the main Sonic the Hedgehog series since Sonic & Knuckles in 1994 and was the best-selling game on the Dreamcast.

After series villain Doctor Eggman releases an ancient monster, protagonist Sonic the Hedgehog vows to stop him collecting the Chaos Emeralds. The other playable characters are flying fox Miles "Tails" Prower, love interest Amy Rose, Knuckles the Echidna, who plans to reassemble the Master Emerald, angler Big the Cat, and E-102 Gamma, one of Eggman's robots.

Sonic Adventure received generally positive reviews for its graphics, gameplay, and soundtrack. It became the best-selling Dreamcast game. A sequel, Sonic Adventure 2, was released in 2001 for the Dreamcast. Enhanced ports of the game were released in 2003 for the Nintendo GameCube and Microsoft Windows. It has since been re-released as a downloadable game for Xbox 360 via Xbox Live Arcade, and PlayStation 3 via PlayStation Network in 2010. It is also included in the Dreamcast Collection for the Xbox 360.