Main Characters:
* Chip (aka. "Light Gaia"): A small, furry creature who becomes Sonic's companion after the world is split in two. He's the embodiment of Gaia's light and is crucial to restoring the planet.
* Dr. Eggman: The classic Sonic villain who, through his experiments, unleashes the destructive power of Dark Gaia. He's less of a straightforward antagonist here, more of a misguided force.
* Amy Rose: Sonic's longtime friend and admirer. She's determined to find a way to help Sonic get back his human form.
* Tails: Sonic's loyal sidekick and mechanic, who builds the "Sonic Riders" that help Sonic travel the world.
* Knuckles: The guardian of Master Emerald, who plays a less prominent role than usual but is still important to the plot.
Other Notable Characters:
* Professor Pickle: A recurring character from the Sonic series, who is often hired by Dr. Eggman.
* Blaze the Cat: A princess from another dimension who is briefly involved in the events of the game.
* Silver the Hedgehog: Another time-traveling character who appears, though his role in the main storyline is minimal.
* Omega: A powerful, robotic antagonist who initially appears as a threat, but ends up aiding Sonic in certain parts of the game.
* Various animals and townspeople: The game features many inhabitants of the world that Sonic visits.
The specific characters encountered vary depending on the specific world or stage in the game.
Let me know if you want more details on any of these characters, or if you'd like to know about other characters from the Sonic franchise!