Comment by WorldMaker

GOG has a strong anti-DRM stance, but unfortunately not all of the games GOG sells are truly DRM-free if you consider things like online services and online service requirements and live patching/live service. Often considered the worst offender is Sony published games with some of the worst root kit anti-cheat installs still bundled in the GOG edition, with mandatory online "data collection" for the game to run, even for single player games.

GOG will still give you an offline capable installer file for that game, and hasn't entirely compromised its values on that aspect of DRM-free, but the game won't boot up offline and/or without agreeing to the data collection terms and installing the rootkit.

I like GOG and the criticisms here are only because I'd love to see GOG do better, but I also know GOG alone can't fight "the cloud" and even single player games from major publishers having "required" online services. It's a DRM of a different sort (and remains a long term archival issue, because few of the companies like Sony will ever unlock the game or open source the service at the end of the games' commercial lives and would seem to prefer to just leave those games unplayable).