Gameplay
Sonic Adventure is a platform game and is the first in the Sonic the Hedgehog series to feature free-roaming 3D gameplay. The game is divided into three types of stages: Action Stages, Adventure Fields and Subgames. The division of Action Stages and Adventure Fields was a serious departure from previous Sonic games. In addition, unlike the previous game in the series, Sonic Adventure has six different characters to choose from: Sonic, Tails, Knuckles, Amy, Big and E-102 Gamma; each with their own style of gameplay. Only Sonic is playable at first, but other characters are made available after encountering them in his story. When all stories have been completed, a final story is unlocked.
Sonic's stages involve high speed gameplay, whilst Tails' stages require him to reach the end of the level before Sonic (and in one case, Robotnik) does and Knuckles' stages see him searching the area for shards of the Master Emerald. All three of these returning characters retain many of their trademark moves from previous Sonic games, though they can use brand new techniques. Amy's stages require her to escape from the E-100 Zero robot chasing after her, Gamma's stages involve shooting through levels to reach a target and Big's stages involve fishing for his friend, Froggy.
Action Stages are the main playable levels for each character, where the player must face various enemies in order to complete their respective goals. Adventure Fields split up the action, where players can explore the surroundings to advance the plot, discover new levels or search for items which enhance a character's ability (for example, the Light Speed Shoes allow Sonic to run across a path of rings). Subgames deviate from the main gameplay of the character, which include minigames such as kart racing and snowboarding. Players may also find hidden Chao Gardens, which allow them to raise Chao, a sort of virtual pet. 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.
Read more about this topic: Sonic Adventure