The following information comes from an article over on GamesBeat:

Scheduled to release Winter 2018.
12-player races online and offline.
4-Player local split-screen available.
Vehicle customization options are available.
Wisps (from Sonic Colors) appear and function as offensive and defensive items.
Multiplayer modes include Grand Prix, Exhibition, Time Trial, Team Adventure and more.
Can play solo, team up with friends or face-off against each other. "If you accumulate enough points on your meter, you can unleash your Team Ultimate power, which boosts other members of your team. The idea is that you'll play as a team and win as a team. The team with the highest score wins."
15 playable characters.
3 character types: Speed, Technique, and Power.
Planet Wisp is a playable track.

QUELLE und TEXT: https://gonintendo.com/stories/310505-team-sonic-racing-more-details

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