On Xbox.com site appeared an announcement stating that
Sonic Adventure 2 arrives on our consoles such as Live Arcade, precisely on 3 October, and will support the offline multiplayer. The page was removed shortly thereafter, but not before a user on NeoGaf has immortalized and brought back images that you find below. It seems that we will have the chance to relive one of the glorious games released in 2001 on the Dreamcast, and we will not fail to inform you about further innovations.