Good morning people,
As a result of a doubt which it has arise and that GOG can't answered me in a rational way (I mean, with a human being instead of a bot), I see me obligated to ask in their own forum.
Recently, I've reached about the "Cloud Save" (the tool that some games possess to save your progress). The question is if the games, which have this tool (because not all games have it), need mandatory internet in order to save the progress on the videogames. This happens, for instance, in steam, or in Epic Games, and in other platforms which have DRM.

I hope this doubt will be answer as well as I will wait with impatience to your own answer.
All the best,
DariiRas

Cloud saves work by saving the game on the cloud, wich means you need internet, otherwise there's no way the Galaxy client can reach the cloud server. (nothing to do with DRM really)
Cloud saves are usefull if you play the same game on several devices, otherwise is not that usefull.

Worth nothing that even if you have no internet the games still work (without cloud saves of course) and you don't even need to use the Galaxy client to play the games, just download trhu the website and install.
If you're unsure, add a free game to your account and try it.

Well, asking a question like that on the forum makes more sense than asking support (it's probably not the best use of their time, plus we're more likely to give you a nuanced answer). I will start with "I don't use Galaxy and therefore I do not take advantage of cloud saves through GoG Galaxy".

That being said, I think you've misunderstood how cloud saves generally work. While some games might directly save progress on to a third party server, this is not how I would expect GoG to operate (indeed, I'd expect only a small subset of online-only games to work in that way). What usually happens is that a game will save files locally and then synchronise the local copies with the cloud both when launching and when exiting the game. This means that if you leave a game when you have no internet, your save will be stored locally. The synchronisation will fail, but your save game will still be on your hard drive. When you next start the game, if you still have no internet, the game will load a local save. If your internet has been restored, best practice is to call a dialogue box that asks you whether you want to keep your local save or replace it with the one on the server.

If you select the former, your local save is then synchronised to the server. If the latter, the server save is downloaded to your hard drive and replaces the local save.

And, another question I have, is it possible to copy the "saves" files of a game belonging to any DRM other than GOG (STEAM, ORIGIN...), and continue playing the same game but in GOG?