Greywolf1: Thanks.
To summarise: There is a game feature which is advertised on the game's store page (German language support, text, audio), but I can't have this feature without installing additional software (GOG downloader) on my PC - which is not mentioned on said store page.
I can't say whether or not this is legal (I don't have a legal background), but it doesn't fit my understanding of business ethics. Good to know!
No. You entered the location where GOG downloader links are located, and I simply pointed out that you where incorrect in your assumption that those were for Galaxy, pointing you then to the actual software they are for (a tiny program that has nothing to do with Galaxy).
The regular HTTP download link, which does not require any other software than the very browser you are using to post here, since it is so important to you, is located in your library. See the attached pictures.