This will also work for Galaxy.

is it still a thing? Had plans to grab this one on GoG, but my friend reported me recently, that stable version there is still 0.5.32.

Also - is there any difference between GoG's binaries and ones from dev's site? I mean - are they drm-free too and require key just to download, access mod portal and multiplayer?

No, the latest stable GOG realease is 0.16.36 (See my above post).
The latest standalone GOG installer is still 0.15.32, but will be updated to 0.16.36 whenever GOG bothers to release it.

Not really, the GOG one comes with a GOG icon, that's pretty much it. If you get it from GOG, you also get access to the one on the dev's site anyway.

so - aside of GoG icon (whatever it means), site version is drm free too?
(e.g no additional checks, no network connections (hello, dont starve!), no asks for key input on 1st launch - just same version, without GoG's features)

Yes.

thanks

How come other games can release multiple patches a week? I would blame the devs here.

Galaxy just updated my version to 16.36.
Well, actually, Galaxy broke my installation entirely. :-D
Doing a verify/repair seems to have fixed it, though.

The game auto updates from the dev's own servers! I really don't understand the complaints.

I see the updates to the GOG version as being my backup in case the dev goes under, I let the game auto-update itself for actual playing.

There Factorio 0.16.51 got released in June yet. Can GoG Team to update on this?

If you are active in the Factorio community, I would ask the devs there.