armaankhan: On Windows, to install html5lib, you use "py -m pip html5lib", and similar syntax for the other prerequisites (replace "html5lib" with "requests" for example). It was pretty easy overall, once Python itself was installed (use the download from python.org; the Windows Store version didn't work for me) with no elevated permissions required in the command prompt. For one of the requirements it'll tell you that you should add a path to your "PATH" environment variable which you do by searching in Start for 'edit the system environment variables" but that's the most complicated thing that getting everything up and running will ask you to do.
One thing to keep in mind is if you have a large library, gogrepoc will take a LONG time to run, at least with the initial update. I have over 1100 games in my library and it took over three hours to get all the info from the GOG website, and importing my collection of files that I'd already downloaded was taking so long that I canceled out of it and ultimately decided to just manually check GOGDB's changelog every day and see if any of the games I own got updates. Gogrepoc's a great script, but it's not suitable for me, which I mention just as something to keep in mind when you try it out.
Thanks.
I'm just shy of your number of games. Maybe it's better to just check for updates, but I'm constantly going back to check to see which version of Fallout I have, or which of the dozen-odd Warhammer I have. That's really faster? I was looking at it, and it was maybe a couple days per page. Granted, there were only a couple games I was waiting on (The Planet Crafter and Terraria) and I'd have noticed them, but it would take a whole lot more than 3 hours to figure out which of the 10+ pages of storefront needs an update.
Eh, maybe it's just as well to stop buying from GOG in the first place...
If its as bad as you say, maybe GOG is not in my future...