Lifthrasil: Thanks. I'll do that.
Gersen: Ok, about NMS, the answer is : it is "complicated".
First if you go with the strictest definition, as in, download the offline installer and nothing else, install it on an offline PC and play it then the answer is : NO, as far as I know and unless it has changed very very recently (didn't retry with the latest version as you need at least 2 hours on a fresh install), you will have access to 99% of the game but some stuff like quicksilver or expedition won't be available offline.
Now, and that's why I say it is "complicated" and it goes back to I would say the "
academic" vs "
emotional" definition of what a DRM is. In short the whole "online" part of the game is not technically a "DRM" but just one of those tentative to make the game more "engaging" / "community'esque" by having time limited events and others online interaction.
What is the difference ? well I would say the main difference, and the reason what I am a lot more "
tolerant" of it for a game like NMS compared to others is that the devs made it in a very "non-intrusive" way. What I mean by that is that the game doesn't really rely on servers for most of it's "online" single player impacting functionality, as in it just need to download a JSON file from time to time and then can be played 100% offline.
And if you don't want to let the game connect you can download said files from :
https://cwmonkey.github.io/nms-expeditions/ and backup them for future use. Which technically gives you a better experience than being online as it allows you to replay past expeditions.
So for the tl;dr; version :
Can the game single player be played 100% offline relying only on the Gog's offline installers ?
The answer is no.
BUT (and for me it is an important BUT, but I let everybody make their own decision) it is possible to create a working offline version by downloading some extra files to simulate most of the online functionality.