Ah, I see. I think it uses the same recommendation system that's used on the store pages, which also doesn't take into account what you already own. Probably wasn't considered worth it to make it more advanced than it is. Given Gog's somewhat smaller catalogue, there's a rather finite amount of sensible recommendations for a lot of games anyway.

If that was the case you might expect games you own to crop up occasionally. This isn't just recommending me things I already own, it's specifically recommending the order I just made quite consistently. What you describe would be a small oversight, but what is happening seems to be much more specific. It seems like maybe it's weighting my "just purchased" items stronger than things I already owned, but someone forgot to exclude those items so it consistently recommends the things you just bought and then fills in the gaps if there are any.

This would be all down to some logarithm.

In the general scheme of things though, this ain't that big an issue, and GOG have far more important things that need fixing first ... one or more of those might even correct this issue.

One of the more important things that is related to this issue no doubt, is when you own something as part of a Special Edition etc, that doesn't show as owned individually. That happens all over the shop, even with Witcher related games and DLCs.

hehe, I had something similar on Steam the other day. The title was "As you played Fall of the Dungeon Guardians" (which is a very good old school dungeon crawler with some interesting team mechanics), Steam whent on to recomend me some... doubious... games like Gal Gun, HunieCam, Sakura Knight, Funbag Fantasy etc. I have to admit I giggled. Not sure how that algorythm worked.... wished I took a screenshot now.

Case in point, there was someone asking what 4X games were on the Luna steam DRM sale, and I wanted to point them to GOG..
Well..there's no 4X genre or tag on GOG. They aren't going to browser through 14 pages of Strategy games for that.

store.steampowered.com/tags/en/4X#p=0&tab=TopRated
(Not active link, because steam DRM..)

https://www.gog.com/games?system=windows_10,windows_7,windows_8,windows_vista,windows_xp&sort=bestselling&page=1&price=discounted&language=en&category=strategy&search=4X

Indeed, it seems like flawed logic: "Let us recommend something in the same vein of the games that this customer has been purchasing recently. Mmmm... Oh, here, it seems these games score highly close to the recent purchases. How sweet! Mission accomplished!"

:-)

Maybe there is a loophole like this: the algorithm checks out the games that are already in the user's possession, but does not include the games that the customer just bought, for some reason. No doubt that the software originally wanted to do that, but...