Saw it on the release list on Steam and was wondering why it wasn't here.

Not really my cup of tea, but Civilization seems to be a popular series.

https://store.steampowered.com/app/241000/Jon_Shafers_At_the_Gates/

https://www.gog.com/wishlist/games/jon_shafers_at_the_gates


According to the wishlist entry GOG refused it.

So? Go let him in, then.

[actually reads OP]

...Oh, it's a game. I thought we had just gotten to point where people (other than fortune_p_dawg or Fairfox :P ) were starting to create threads about the mailman having just left, or having seen a person you thought was someone you knew, but who turned out not to be.
Carry on. =)

but that REALLY did happen... once.

Read about the game a few weeks ago and I'm also interested. Checked the official forum (which is quite empty) and after release now the Steam forum. I also watched some gameplay videos on youtube.

To put it simply, regarding the forum and the critics the game is not really finished yet and better should be still in early access. Jon Shafer posted a post-release update plan, he wants to fix the important stuff within 5-7 months. Knowing that the game kickstarted six years ago that's kind of ambitious. I'm still interested in the game, but I will for sure wait for the update 1.3 in 7 months and then see the state of it. I guess gog came to a similar conclusion.

Post-Release Update Plan
https://steamcommunity.com/app/241000/discussions/0/1744480966986474404/

Update Plan & Tasklist
https://steamcommunity.com/app/241000/discussions/0/1743358239834179395/

Edit:
Btw, you can get a drm-free version and steam-key of the game by buying directly from his homepage. By going this route he will also get a bigger slice.
https://www.atthegatesgame.com/purchase/

I'm so sad GOG refused it.
Even sadder than when I failed to kickstart it and made it impossible for me to get the physical edition. :'(

Far too expensive for what it is imo. I'm not suprised gog rejected it according to my sources they also rejected doorkickers action squad and a number of other games; the idiot in charge on that department at gog must be mad.