Is Game Center information stored on the device or servers?
I restored my iPhone 4 and logged in with a new Apple ID. I purchased Age of Zombies on it and loaded it up for it to give me around 20 achievements. I played this game before I restored it but it was on another Apple ID not associated with the Game Center account I'm using now. I changed my Game Center nickname to my old one as well and changed my old one to something random but I don't think that has anything to do with that cause people change those often. Ideas?