One of the first Dreamcast remastered games to hit both Sony and Microsoft's online stores was Sonic Adventure HD. While it wasn't exactly a well done remaster thanks to its lack of certain features the original game had and the horrifically boxed in visuals, it seems Sonic Adventure 2 HD will be pulling all the stops to give us the expeirence we should have had in the first place.
And this new information is all thanks to a preemptive listing on the Xbox Live Marketplace accessible through http://xbox.com's official website. Included in the listing is the game's official description, ten new images of the game's updated graphics (in widescreen!) and even a picture revealing that the hugely popular chao battles will be making a return.
The release date listed on the marketplace is October 3rd, 2012. You can view the marketplace page below, but in the event that the marketplace page gets taken down, I've also added all of the images to a nifty little gallery.