I'm looking really forward to this game myself. When I first heard about it I went into a fangirl fit, then calmed down and became uncertain, but the more I hear about it the more appealing it sounds.
Shadow has the option of using weapons, he's not automatically equiped, and it also sounds like he has time-bending abilities. Everything you do also aparently effects the ending's outcome, meaning it sounds extremely unrestrictive and will probably have multible endings, giving the playback value an extra boost.
Sonic, Tails, Knuckles and Eggman are also all there it would seem. I'm curious to see how they fit in.
All in all, I'm looking forward to learnig more about Shadow himself. He's an enigma, and I'm hoping this game will answer those questions and fix the gaping plotholes Heroes ripped open. The idea of actually being able to decide whether or not Shadow's a hero or villain is also pretty sweet.
My only real complaint in general right now is the graphics. They're not even trying to make those weapons look natural in Shadow's hands it would seem.
... Huh? Okay, now this doesn't make much sense O_o Go to
http://e3.sega.com/ and check out the Q&A on Shadow. They're claiming Shad was in Sonic Adventure, then made a return appearance in SA2.
Weird.