Slay the Spire's free fan mod expansion Downfall is exclusive to Steam.

Yet another inferior scam gog version of a game to remove from my wishlist.

I tell you what the devs tell me, they didn't see it as a official patch, they public the official patchs in the update tab, just like it happen with this latest one. As soon as they release a new officil patch they bring it to GOG at the same time.
This should count? I mean, it's not the devs or publisher fault, maybe if we talk with the modder they can bring it here too.

If you want to waste your time asking, go ahead. I'm doing gog's job for them unpaid myself.

Ultimate Fishing Simulator is missing this update:

https://store.steampowered.com/news/app/468920/view/3227412906500097198

I have to agree with Ruvika here. It is NOT GOG's job to bring mods here or to ask modders to modify their mod so that it will work with GOG as well. Everything that GOG concerns are things regarding the original game - not fanmade additions. If this is however an update of the original game that ALLOWS modders to mod the game it is a different thing and it would belong here.

Apparently it's a mod, but it's officially approved by the original developers and has its own page on Steam, it seems like a borderline case.
https://store.steampowered.com/app/1865780/Downfall__A_Slay_the_Spire_Fan_Expansion/

Thanks for the link and the explanation. I just used it to enter their discord and ask about a GOG version. Will post if I get an answer.

Ziggurat 2 appears to be missing its latest update and the one before it as far as I can tell:

https://store.steampowered.com/news/app/1159560/view/3328736287863375648

https://store.steampowered.com/news/app/1159560/view/3131695559754448561

Got my reply from their discord. It seems the devs of the mod aren't aiming to bring it to GOG officially BUT I also found this:

https://www.reddit.com/r/slaythespire/comments/gj5kel/howto_add_mods_to_gog_version/

Edit: Removed to avoid a thread lock seeing as how CDP/GOG are looking for excuses to lock threads now.

Expeditions: Rome has received the most recent update, bringing it on par with the Steam version.

Did a few to show a new helper how to handle the list.
Post 3193 is next.

Helped out with some entries, up to post #3217.

Doom 3 on Steam now costs 10 bucks, and comes with the original version, the expansion and the BFG Edition, in contrast to GOG that only has the BFG Edition and costs 20 bucks.

It cost 10 bucks here now, but still doesn't include the original base and expansion.