|genre = Platformer, action-adventure
|modes = Single-player, multiplayer
is a platform video game developed by Sonic Team. It was originally released for the Dreamcast as a launch title in Japan in 1998, and worldwide in 1999. It was the first game in the main ''Sonic the Hedgehog'' series since ''Sonic & Knuckles'' in 1994.
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.
''Sonic Adventure'' is a platform game in which the player controls six different characters: Sonic, Tails, Knuckles, Amy, Big, and E-102 Gamma. They must stop Doctor Eggman from stealing the seven Chaos Emeralds and feeding them to Chaos, a monster known as "the God of Destruction". The first in the ''Sonic the Hedgehog'' series to feature free-roaming 3D gameplay, ''Sonic Adventure'' features two game modes: Adventure and Trial.〔Sega, p. 7〕 There are different goals for each character in the game: Sonic involves high speed gameplay, while Tails must reach the end of the level before Sonic does, and Knuckles searches the area for shards of the Master Emerald. Each of the three characters retain many of their trademark moves from previous ''Sonic'' games, such as Tails being able to fly for short periods of time, and Knuckles being able to glide through the air, though they can use updated techniques as well. The rest of the playable cast is rounded out by Amy, who must use her hammer to escape from Eggman's E-100 Zero robot chasing after her, Gamma, who must use its laser beam to shoot through levels to reach a target, and Big, who fishes in efforts to find his friend, Froggy.
The "Adventure Mode" is a one-player game which consists of two areas, the "Adventure Field" and an "Action Stage".〔Sega, p. 9〕 The Adventure Field contains several "Events" that are encountered in the course of the story, while the Action Stages have each character fulfilling a goal to clear the stage.〔 Players may also find hidden Chao Gardens, a protective environment inhabited by Chao, a sort of virtual pet. The player can hatch, raise and interact with a Chao.〔Sega, p. 15〕 Chao can be taken with the player by downloading the minigame ''Chao Adventure'' to their VMU, or in the GameCube version, a Game Boy Advance with ''Sonic Advance'' or various other Game Boy Advance Sonic games. The player can also raise their stats by giving them small animals that they found by defeating the robots, which improves their performance in Chao Races. There are also eggs hidden throughout the Adventure Fields which can produce special types of Chao.
By playing through Action Stages and Subgames, searching through the Adventure Fields or winning Chao Races, players can earn Emblems. In the case of Action Stages, each one has three Emblems, which can be earned by replaying the stages and fulfilling certain objectives, such as beating the level within a time limit. In ''Sonic Adventure DX'', these can unlock hidden extras such as Game Gear games.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』