Sonic Adventure

Sonic Adventure is a 1998 platformer developed by Sonic Team, the blue hedgehog's ambitious leap into 3D and a signature launch-window title for the Sega Dreamcast in Japan. It weaves together six playable characters, each with a distinct play style, into a single overarching story about the ancient water creature Chaos.

Gameplay ranges from high-speed, forward-momentum stages as Sonic to exploration-heavy hub worlds, treasure hunting with Knuckles, shooting sections with Tails and Gamma, and even fishing with Big the Cat. Adventure Fields link the action stages and house townsfolk and side activities, while a Chao-raising virtual-pet feature added surprising depth. The whole package showcased the Dreamcast's power and pushed Sonic toward story-driven, character-heavy adventures with full voice acting.

The game was a commercial success, becoming the Dreamcast's best-selling title, and shaped the direction of the series for years. It has been re-released on later consoles and digital storefronts, so modern players can experience this early 3D milestone without original hardware.