When you first start the game a local account gets created. You can use this local account only on the device the game was downloaded to. It cannot be transferred to any other device and can quite easily be lost if you delete your local account or change it with another account.
You can save your game account by connecting it to Google Play Games. You are supposed to be logged in to Google Play Games by default:
- Make sure you're logged in with an account that has no other Little Big Robots accounts connected to it;
- Restart Little Big Robots;
- Open Little Big Robots and connect it to your Google Play Games account via the in-game "⚙" menu.
That's it. Your progress is now secure.
The above will work only in case you don't already have another Little Big Robots account connected to your Google Play Games account. Otherwise, you’ll see a pop-up prompting you to choose between your old game account that is connected to your Google Play account, and your newly-created local account. If you choose the old one, you’ll lose access to the local account.
To save it, you should bind it to another Google Play Games account.