Endless Roll Glitch
Go to Metal Harbor. When you come to the area where you must roll under the grating, go to the left corner and try to roll under the grate and into the wall at the same time. If it doesn't work, try again. If done correctly, Sonic will start rolling in place and won't stop until you press the A button. The fire ring might be needed, I'm not sure.
If you need more help, we've got more Sonic Adventure 2 Battle cheats and also check out all of the answers for this game
Comments for this cheat