Hello Taylor847,
Thanks for using the Apple Support Communities! I understand you unlinked a game from your Apple ID. I'm happy to help you find some information.
First, I would suggest that you Sign in with your Apple ID.
Have you uninstalled the app? If so, you can redownload the app and try to sign in as you normally would. Here is a link to help you:
Redownload apps, music, movies, TV shows, and books
If you're still unable to link your Apple ID to your game account, you'll want to contact the app developer. You can find their support site here: Community Center
Have a good day!