PafcioPrime: version 2.0.0.2 from your link is a web installer which installs the newest version.
You can check your gog version by going "top-left cog > settings > bottom-left of the pop-up window".
There are few standalone installers on that link. Those are proper older versions. I tried "1.2.67.58" and "2-0-30-20" - those install gog launcher properly, but I am unable to install the game.
I am not sure what you did to make it work, for me it does not work.
Hm, strange, yes, when you mentioning here.
I looked just now on the installer, and it has indeed only 1Mb.
But i see, i have another installer there Version 2.0.46.133()exe with 270mb.
Maybe its that one, what i have installed, because i can not see the version at the client.
It can be found here
https://www.gog.com/forum/general_beta_gog_galaxy_2.0/online_manaual_exe_file_for_gog_galaxy_2047_gog_galaxy_not_updating You should not need to install the game. Just go to "owned games" then click at the top midle at the "+" and search for "No man's sky"
It should add it, but i cant say right now, what the exact steps are, since it is already installed.
You may look by yourself a bit around, what you can do at the top, because there is also an icon to manage the installation.
By that you should can link the game to your Galaxy client. And maybe update it by starting 2.0.77.
Edit:
Well, it seems i got it already updated.
The one what worked with Mulitplayer is 2.0.77.22-Beta,
the one what doesnt, but updates the game so far is 2.0.73.27-Beta.
Below 2.0 may do not work, because they wrote, multiplayer is only available since 2.0 and Windows 10.
I installed them both from the Lutris menu with the cross and search on Lutris Webpage for GOG Galaxy,
but selected "install from file".
If i only run the installation through Lutris, GOG Galaxy doesnt really work.
I also pause all downloads before i play the game if there are any.
Right now, i dont see other player too, but sometimes it feels like that there are no people online,
since GOG is not crossplatform into the Steam users?
But sooner or later it did always work.
Edit2
Yes. After starting the game again with 2.77.22 , loading into the anomaly, i did hear the noise of other ships,
deactivating Multiplayer and enable it again, it shows at least one player.