Hello @AndyGOGGalaxy -- can you see a notification if I tag you this way? Are you still the right person to turn to for these things, like the issue on May 5th? If you don't get an official answer here, open a support ticket. If I recall correctly, issues like this have been fixed without a client update. So GOG might fetch the database from IGDB, and then GOG Galaxy fetches that database from the GOG servers.

I'll send in a ticket, nothing to lose.
Edit: The game is now listed, so the issue is resolved.

AndyGOGGalaxy is the right person to "ping", but I'm sure that using the "@" doesn't do anything, I just prefer to use it anyway.
Sometimes games won't get added day one here, see also this post. You're right, no client update is needed (only cleaning cache, if they fixed an integration issue).

I would also like to welcome you on the GOG subreddit, since I saw you signed up recently :)

It's there now, so this thread can be marked Solved. I guess a support ticket would be the only option then. But in this case at least, support wouldn't even have responded by the time the game got added. Thank you. I'm not sure about long-term prospects there. I got downvoted for spotlighting some giveaways here on the forum. The people who do this don't explain themselves, so I have no idea what they disliked. I've also seen a newsletter discount post get an overall positive rating, while my own post somehow attracted people who hate the game and got downvoted to 0.