Minigalaxy lets you download, install and play your GOG Linux games without getting in your way.
Besides all that, it offers the following additional features:
An account on gog.com is required to use this application.
It's a good launcher and works when Wine/Lutris usually fails. But, to get DLC's/Expansions is almost a gambit (usually takes a few tries and some patience/luck).
It's pretty neat but recommend downloading the latest version instead. https://github.com/sharkwouter/minigalaxy
You "only" have a library of compatible games to play on your Linux system - no addictional contents, no services. It is not like the Windows counterpart, but for some people, this is a plus. It uses Wine; for games that works through DOSBOX (almost any GOG game), since it is available on Linux, this looks like a lazy workaround. To launch a game, you have to launch the platform before, and it is quite slow and heavy. But after all, you can play classics like Baldur's Gate or Diablo on your Linux system, this is exciting.