I want to propose this:

Users have to "activated" their review-rights and get rankings (visible for admins).

1. They have to choose a game they bought, downloaded (and played via gog galaxy) but never reviewed. Or they have to choose from some proposed games they probably could like or may have played.

2. They get asked about if they ever played it and if so, the GOG or the retail/steam version.

3. Users need to write a short review and give the game a rating.

4. GOG checks the review for reasoning, arguments, choice of words, etc ...

5. GOG rates (like) A - User is trustworthy , B - User is blinded by hate/nostalgia, C-Troll ... and every time after that, the A ranks pop up first and get their reviews published faster. C´s may could write something good, but their priority is lower.

How is that ?

Point 1 invalidates point 2.

No, because if you have it in your library but (since you dont use galaxy) there is the possibility you never played actually the GOG version. (maybe there is one download listed for the game, but you know....)

Just to get sure, you HAVE played it. And to figure out where you spent more time: GOG Version you bought sometimes during a sale or the Retail - about 20 years ago....

Just as an example:
I have bought Praetorians (Pyro Studios) and Imperial Glory on GOG just a few weeks ago. I never had time to play (wating for vaccation) those versions. Imperial Glory - i bought it because i am a PyroStudios Fan and never played it before... BUT i played Praetorians like day and night back then (the CD Version).

Ah right, sorry it's just badly written and badly read.

Sounds like too much work for Gog's staff to be honest.
I also don't like linking the right to write a review to using Gog galaxy (don't intend to ever use that).
Point 3 sounds almost like you want to make review-writing mandatory? Not going to work.
I think in general you're somewhat overestimating the importance of reviews, at least for old titles. Yes, there are too many that are driven by nostalgia...but given the low prices for old games the potential for making a serious misinvestment isn't that great.
Just adjust your expectations when you're reading "best game ever" reviews for games from the 90s.
Don't know if there are problems with reviews for newer or more expensive titles since I don't buy them (apart from the occasional adventure).

deleted

Hey, no problem :-) And as I said, I agree with you...some of those "best game ever" reviews by people who are viewing their old favourites through rose-tinted glasses are pretty silly. Just don't really see a realistic solution for this. Reviews are bound to be highly subjective anyway.