How Can I Make A New Account?

If you wish to add another user, you will need to create a new Game Center account. For more information about how you can create a new Game Center account, please visit:

http://www.apple.com/game-center/how-to/

Once you have created a new Game Center ID, you can simply switch users in Tunnel Town by tapping the settings icon on the bottom right side of your screen. Then, tap "switch user" and select the new Game Center ID you have just created.