Yes, you can play as a guest user however, you cannot continue your game on other devices and once you've uninstalled the game, you will lose your game data. Game data that isn't registered with a Facebook account is kept within the app cache of your device and therefore, once the app data is cleared or deleted, game data and progress will be erased.

Connecting to a Facebook account is our method of keeping your game data intact. It is not possible to unlink it once you have registered the account. Registering with Facebook keeps your data on our servers and as such, you can also import your data to other devices once you login.