vv221: You should buy Factorio
from the developers website, this way you are sure to always get the best version of the game.
This is the version I have, and I never spotted anything looking like a DRM in it.
No matter where you buy, you get a code to register on their site anyway.
Robette: I played the demo on Steam and consider buying the game here. However, some reviews indicate that there is some poor pseudo-DRM involved (and some complaints about a missing campaign in general?). Can anyone confirm what the current state of Factorio is on GOG (als in terms of updates comming in time) and if it is worth puchasing here or if I could go for Steam just as well?
If you buy it there you get a key that lets you register your purchase on their site, which gives you access to the most direct way to get the game. Even if GOG is slow with updates you can just bypass that entirely.
As for psuedo-DRM, the game has an optional auto-updater that does require a login. The login isn't required to play, just to download new versions (which is no different from logging into your GOG account to download a new version).