clarry: Yep, that looks fair enough.
I think the issue here is related to nameservers and/or GOG's CDN (or both). In fact, I just tried enabling trr in firefox and it breaks the site for me; ends up looking much like on your end. I don't know how to get debug output from it so I can't tell whether it's a failure to resolve, or if it's resolving to servers that do not behave.
Can you try Google DNS? How to do it exactly depends on your OS. There are some instructions here:
https://developers.google.com/speed/public-dns/docs/using I changed the DNS following the instructions on your link and I'm happy to report it fixed the problem! It also fixed the problem I had with Youtube user pictures, which had been driving me mad for months. Thank you so much for your help, you're the best! :)
SLM-1: I have the same problem. A week ago it was ok.
jkiiskinen: I'm also having this exact same issue. In browser console, I see ERR_SSL_VERSION_OR_CIPHER_MISMATCH errors for some css and js files that fail to load (screen1). Connection is secure and certified (screen2).
Changing the DNS server fixed my problem, I hope it also works for you both.