The registration works for all the game sub-domains: sign up on one of them and you log in to any of them with the same account.
Only the login and the password are required. The e-mail and the phone number are up to you, but:
Once you have signed up, you can already play single-player games.
In the same window, below the button, there is “Sign up with Google” (“Sign in with Google” on the login tab). No password is needed: from then on you log in with a single button.
Google asks which account to use every time — that is deliberate, so that nobody signs in as somebody else on a shared computer.
What happens next:
ivan.petrov); if that one is taken, it adds a digit;Look at your login and remember it. Password recovery looks a person up by login, not by e-mail — and the login was made up for you.
The button may be missing altogether: only the sites that have set Google sign-in up show it.
If you press “Sign in with Google” and you already had an account on the site, the engine finds it by the e-mail address and lets you in, linking Google along the way.
If there is more than one account with that address, it asks “Which account do you want to sign in to?” and lists them, each with its login and name. The one you pick gets the link. At the bottom of the list, in a group of their own, there may be accounts that carry this address without having confirmed it.
Close the window and nothing is linked — you go back where you started. The question lives for ten minutes and only in the browser you started in.
Google can be linked later to an account you already have: profile → “Account” → “Sign in with Google” → “Link Google”. Any Google account will do — the link goes to the profile you are sitting in, and you will not be moved into somebody else's.
It is unlinked in the same place, with the “Disconnect” button. But the last way in cannot be unlinked: if there is no password, set one first.
How to set a password if you never had one: profile → “Account” → “Change password”, and leave the “Current password” field empty. The dialog does not say so, but an empty field matches an empty password.
If your address in Google differs from the one in your profile, it will not change by itself — a “The address from Google” card with a “Use this address” button appears in your profile.