Schwertz: And that's true.
But not all games here are:
1. Feature-complete.
Since some publishers prefer to remove some DRM-protected components and features in the GOG-specific releases. Usually it's multiplayer- and online-related things but not always.
2. Spyware-free.
Some games (even single player) will still attempt to silently send some statistics or telemetry somewhere. And this fact will not be covered by EULA. Paradox but sometimes the recepient for those data is Steam.
3. Completely DRM-free.
Because:
3a. Some games will require to agree with 3rd-party EULA and/or register on the 3rd-party service to get access to multiplayer features, online features or even restricted by vendor repositiry of the fan-made content.
3b. Some games (relatively old mostly) will require user to have an unique online identificator like a serial number. And a number of sold copies of the game may be greater than a pool of the available identificators.
So, I believe,
SeanDestroyU should ask a more specific question before going for the purchase.
P. S. And, unfortunately, someone else should answer this more specific question, since
Wolfenstein The Old Blood is out of the field of my interests as a game.
What I am looking for is the usual definition most have for DRM free and that is wanting a game that will run offline and has it's own installer just for the game and nothing else. Also the fact that I have to even ask this question on GOG is sad considering what the company started out as. Even more sad is that a GOG moderator / company rep hasn't even jumped in and told me the answer.