The sequel is out now, so be sure to check it out! It's called "Sonic vs. Shadow 2: The Chase", but it's labeled "Sonic vs. Shadow 2: T.C.". Enjoy!
If your having trouble finding the easter eggs, here are some hints:
Easter Egg #1: Secret Chao Menu
It's during the Super Sonic Scene. You'll see it in a place you probably won't be paying attention to...
Easter Egg #2: Secret Scene
It's in the final outtake scene, and it's not Mega Man's little cameo in the bottom left of the screen...
If you e-mail me, I'll tell you EXACTLY where they are and what they unlock (if you ask).