I'm disappointed to see that it's for the Most games are not that easy Build a huge library if you only need to pay $ 1 for a bundle If you want users to close the gap there is an option for "manually added" integrations with You will be redirected to a GitHub page that lists the integration requirements and even includes Battle.net and Itch.io platform IDs. I suspect GOG is taking an attitude that says "if you build it, you will come".
You can sign up for the closed beta, but it may take a while for you to gain access. Honestly, that's fine, as there's so little to offer right now, it's easy to lose interest. However, once this thing goes public with a whole host of integrations and a few more features, it may be time to say goodbye to those spreadsheets.