OK, I figured we'd might as well. I know I'm already psyched for this game.
First, I would actually guess that we've only seen two "continents" in the gameplay video. I don't know about the rest of you, but I think the background of the desert-city-thing looks far too similar to the background of the giant trees. Could that really be one large stage?
I also want to know what Antarctica would look like, I don't know if they're specifically going with Earth's seven or if they're trying a different tack.
I would expect Werewolf Sonic to be a far slower but far stronger version. That probably isn't a good thing, we've had far too much slow lately.
I also have a feeling that not many other characters will appear - it just doesn't seem like they will. I even further doubt that any other characters would be playable.
I think we can infer that Super Sonic will NOT be playable in this as well.
That's all I have for now, let the speculating begin!