Quoted By:
Actual Spoilers for those who wanna know the story but don't wanna play the game:
Those Chaos looking creatures are aliens, their home world was destroyed by the big bad of this game
Their world is also the native home world of the Chaos Emeralds and they use it for all their tech
They fled their exploding planet and settled down on earth, unfortunately they were followed
Cyberspace is their giant digital archive of their culture, beliefs, etc. Sonic can somehow use his own memories to shape his environment and escape it which is why all the stages are rehashes
They tried building the Titans to fight back against the evil, but they still got fucked and had to settle for sealing it away in Cyberspace
The Koco are their souls inside of little charms they had with them
Other civilizations like the Echidnas eventually found the Emeralds and tried to use them a la Sonic Adventure 1. This also sort of explains why Chaos and the Chao are the way they are
The big bad of this game is trying to trick Sonic into releasing it. Which he does almost killing him if not for his friends intervention
Sage is not the bad guy, she's an AI daughter created by Eggman. She and him go through a whole arc. They team up with Sonic to defeat the evil. She dies, but is then immediately brought back by Eggman after the credits.
As far as narratives go, this is the best we've gotten from a modern Sonic game in recent memory thanks to Ian Flynn. Sonic and his friends also have their characters unfucked by Colors-Forces era writing.
