I am currently looking for a working GOG downloader alternative which can download all purchased games under Windows or Linux shell.

Sadly, all alternatives listed on http://www.gogwiki.com/wiki/Download_Clients do not work anymore due the change to the login process (and other changes).

I was going to point you to those, but if those don't work any more then I'm plum out of ideas.

Is it mandatory to be a GOG downloader alternative, coffeecup?

If you like Firefox, I'd recommend you the DownThemAll! plugin, instead. Works like a charm!

(since I found out it, many months ago, I haven't used the GOG client anymore... Just sayin') ;)

PS: Not sure about the Linux shell part, as I sadly don't know anything about said OS. :(

It would be nice if the official GOG client (and the Steam client, and and and...) had a "download all your purchased games + extras" button, but in a way I can understand why they don't do that. Because then many people might actually do just that, even for games they don't necessarily intend to play in the near future, if ever. :)

I don't recall which of those 3rd party downloaders was the one with that possibility, too bad if it is not maintained anymore.