Thief Simulator: GOG version 1.45. Steam version 1.7.12. Also, there is a special DLC (not free) Luxury Houses.

Punch Club: The game has the DLC but not up-to-date and will probably never will! The devs pretends high piracy happened because of the GoG version! And they will not fix the bug to force pirates to buy it on Steam. Of course this is 100% BS because the last Steam version is available on pirate websites.

I have “sampled” many more titles that included a hacked steam DLL than the GOG versions. I don’t repack games myself but from my experience, it doesn’t seem Steam must be that much harder - and on top of that, more incentive by having the better updates!

Firmament.

During dev and initial promotion/crowd funding, the Proof Of Concept (POC) build was available for certain backer tiers.
This build was only directly available for backers who were Steam users.
It was _NEVER_ made directly available for GOG backers. GIOG backers were required to give up on their principles and join Steam to be allowed to access the POC build.

Missing achievements.
The game shipped on GOG, without achievements.
The game shipped on Steam with achievements

Patches.
GOG is still on original initial release - 1.0.0-Release-Day-0 (64655)
Steam is already on Patch 1 - 1.0.0 e9752-p17329
Steam forums link - Patch 1 is out (including missing speeches fixes!)

According to comments the latest patch make the game crash, probably will release the latest patch with a fix later, it's not convinient to release a patch in other stores if you know is broken. On the archivements side of things, I think that goes on another list. Have you tried to contact one of the developers? Probably they can add it when they release another patch. In my case (probably the same goes to other users), archivements are not a big deal, many users don't use the launcher, but always is good to have them. Try with discord to see if a developer can do something.

I know about the CYAN GAMES official Discord server, and the Firmament channels on it.
firmament-story-chat
firmament-bugs-n-tech-issues
Before the firmament-bugs-n-tech-issues channel was started, Cyan was telling users on Discord, and in the Kickstarter Update #57 - LAUNCH DAY! , to email support at Cyan, about bugs found.

The point I was getting at, was not merely that Steam is getting the latest patches first.
It was that both game content and game patches are on Steam, but not on GOG, and that is has been that way since the start of game development.
That is quite definitely a case of GOG gamers being treated as second class, if not worse, by Cyan.

edit: try to fix URL formatting

That's tracked in the List of broken achievements thread, where it was pointed out 3 days ago.

For the choice of "which store first, if we're going to wait for feedback before uploading elsewhere", Steam's developer agreements require the developer to choose Steam, AFAIK. No choice to round-robin which store gets the shiny-but-undertested releases first.

Maybe complain to a monopoly regulator or consumer protection organisation, if you've got the time and energy to do so?

Thanks Ice_Mage, I'd not seen that thread.

Not sure what happened to Daedalic but it seems their published games don't get any patches on GOG...

- Wildcat Gun Machine - missing two patches
- Children of Silentown - missing one patch
- Rough Justice: '84 - missing three patches
- Life of Delta - missing two patches

Maybe I'm paranoid but I can see a pattern...
So better think twice before you buy The Lord of the Rings: Gollum.

I just contacted them on Discord. Let's see if that helps.

I understand your point, I'm just saying that I understand the devs too, updates cost money and time, from both the developer and from GOG, if the patch you released is broken I don't see no point in release something with a problem just for the sake of being on par with Steam, the same happen with another game I don't remember the name, the latest patch and official for now broke the game, the Steam player can't play their game, GOG never recive it, with is something bad from one perspective and really good from other, I prefer a game that is playable.
Cyan update their games, probably they will release the next patch at the same time if it's good.

The problem with doing things where only one store gets the updates, while the others do not, is then you have to develop and distribute 2 completely un-synchonized update versions.
One patch/update for the store (Steam) which is kept current and up to date.
The other stores (like GOG) are deliberately allowed to fall further and further behind, and then they require a completely separate patch to be coded, tested, and released.
Doing things this way, wastes dev time, company resources, and money.

I've tried that route with their long outdated gog versions of Deponia, but got ignored.

Thanks for the warning. I'll jot down a note on my wishlist to check if it's still outdated.
I e-mailed them. I got an automated response confirming the games are still supported, then nothing.

Even Humble got "the complete journey", but they never bothered to bring that to GOG.
Instead we got a "collection" containing the 4 legacy versions.

The "complete journey" isn't complete. It lacks the fourth game in the series. The GOG collection is the better option.;)