My first guess is Starfall Island could be an alien spacecraft that landed on Sonic's planet and became an island. But that doesn't explain the foliage on it that looks like it would of been there for centuries.
My other guess is Sonic probably goes planet hopping again. This isn't exactly a new thing since Sonic Colours, especially SC:Ultimate we had lately, it's just I'd rather we don't blur the lines between what is Sonic's world and what is Earth again.
May be the alien spacecraft has garden in it and after it landed thousand years ago, the seeds from the garden would become the current trees and the grasses.
Knuckles would of been an interesting choice.
Yes, given that he's appearing in the movie recently, I wonder why they use Shadow instead of Knuckles.
Still looking forward to it, even if I'm probably hyping myself up for an anime I may find mediocre just for the Sonic.
The manga itself is already great even if it removes all SEGA related things.
Anime version .... well, we'll see.
Not all anime are living up to its manga version.
Magister Negi Magi, Kishin Douji
Zenki, and The Greatest Demon Lord is Reborn as a Typical Nobody are all good manga that I love but I really hate their anime versions.