Here is an overview of the game, via SEGA:
Worlds are colliding in Sonic the Hedgehog’s newest high-speed adventure. In search of the missing Chaos emeralds, Sonic becomes stranded on an ancient island teeming with unusual creatures. Players will battle hordes of powerful enemies as they explore a breathtaking world of action, adventure and mystery. Players will accelerate to new heights and experience the thrill of high-velocity, open-zone platforming freedom as they race across the Starfall Islands. Welcome to the evolution of Sonic games.
- Experience All-New Open Zone Platforming – Race across the Starfall Islands, brimming with dense forests, overflowing waterfalls and sizzling desert landscapes, each with their own unique action-platforming challenges and hidden secrets to uncover.
- Unparalleled High-Speed Freedom – See what each island has to offer at the speed only Sonic can deliver. Players can blaze a trail as they see fit and discover side quests, solve puzzles, scale enormous structures, go fishing and encounter a friendly face or two along the way.
- Challenge Yourself in Cyber Space – Discover portals scattered across the islands and race through every Cyber Space level, featuring signature 3D platforming at Sonic speeds and many challenges to put your skills to the test.
- Cyber-Powered Combat – Players can use the all-new battle system and skill tree upgrades to fight strategically, combining moves such as dodges, parries, counters, combos and the new Cyloop ability to take down mysterious foes and colossal titans.
- A New Adventure Full of Mystery and Intrigue – Become Sonic and uncover the mysteries behind the remains of an ancient civilization plagued by robotic hordes. With nothing but a handful of questions and a disembodied voice to guide him, Sonic sets out to save his friends and the enigmatic inhabitants of the Starfall Islands from a colossal, mechanized threat.
Watch the trailer below.