As I dig through more Climax stuff, there are a ton of pitches like this where it isn't clear how far exactly they went, but they aren't out of the realm of possibility for things that could have happened either.
Huh, interesting. Kinda glad the idea was scrapped though, lord knows the series had enough grim dark at the time did we really need more? Also the idea of Shadow having his own universe just went completely against Shadow's actual backstory so the idea didn't even make sense from the start.
I have to agree. It sounds like a bad fanfic, and the grim environments would probably get old fast. Chill. It was just a pitch made to Sega. It never went beyond that as far as we know.
Maybe the Black Arms are like the Ing and have their own stygian mirror reality, and Shadow could access it inherently. Tonally it stinks, but maybe there could've been some worthy mechanics in that premise. At least it isn't more dakka.
+1 for Metroid Prime 2 Are we sure that vestiges of this didn't make it into 06? Or perhaps that odd grimdark mentality just permeated everything Sonic at the time.... because Sonic 06 tried to be really serious as well.