Sonic & ALL-STARS RACING TRANSFORMED brings together five iconic characters from the world of Sonic to compete in high-speed racing action. The story revolves around Dr. Robotnik's plan to exploit the power of Chaos, a malevolent being that feeds on the energy of the Chaos Emeralds. As players choose their character - Sonic, Tails, Amy, E102 Gamma, and Big the Cat - they embark on unique racing experiences, each with its own set of challenges and objectives.
Gameplay in Sonic & ALL-STARS RACING TRANSFORMED focuses on speed and strategy as players navigate through various levels. Each character has distinct abilities and strengths, requiring players to adapt their driving style to succeed. The game features a variety of modes, including racing, team battles, and the Chao garden, where players can raise baby Chaos and engage in online racing.
Additionally, players can unlock extra emblems by completing objectives within each level, although these do not affect gameplay. The game also includes downloadable content, such as bonus levels and themes, which were previously available through SegaNet but are no longer accessible due to the service's shutdown.