Sonic 06 isn't the sonic adventure engine at all it mght be inspired by it but in no way does it play or feel the same at all...
Nah, it's pretty much the same. Hub worlds, (yes I know SA2 didn't have one), alt characters with different styles of gameplay, same characters in different levels, multiple sides to the story...
It's basically a shitty version of SA1.
Other than the Advance/Rush Series and Generations, I haven't paid much attention to Sonic since Sonic Adventure came out.
Well its more that Beef links to it a lot. I've never played Sonic RPG.