What signing in with Google shares
We ask Google for one scope: openid email profile. That is the smallest set that lets you have an account, and Google shows you the same list on its own screen before anything is shared.
From it we receive four things and store all four: your Google account ID, your email address, your name, and the web address of your profile picture. We also record when you last signed in.
We never receive your Google password — Google handles the sign-in and we never see what you type. We do not ask for Gmail, Drive, Photos, Contacts or Calendar, so Google does not offer them. And we keep no Google access token, so we cannot act as you, and neither could anybody who broke in.
Everything else on your account — coins, badges, results, display name, settings — comes from playing, not from Google.
You can download all of it or delete the account from Settings, and you can withdraw our access from your own Google account at any time, at myaccount.google.com/permissions.