How can I stop multiple Apple IDs from sharing the same Game Center account?

Game Center is managed separately from the Apple ID used for App Store purchases, so simply changing the account in the store may not switch your gaming profile. Open Settings, tap Game Center, sign out of the current account, then sign in with the Apple ID you want to use. You may also need to sign out inside the game or clear its saved data, depending on how that game handles progress. Be careful, since switching accounts can make your existing saves or purchases unavailable.

Using multiple Apple IDs may not create separate game accounts if the game has already linked your device or saved progress to its own account system. Check the game's account settings and make sure Game Center is signed out before launching it again. Some games permanently associate progress with the first account used, so a separate in-game account may be required.