This is very troubling, and means I should probably start checking out if a GOG game is for sale at Itch.io or even ZOOM Platform, and getting the game there instead.

GOG really need to resolve this issue.

If Goldberg can do it, so can they.

Isn't Zoom also client-driven?
For example, the latest patch notes for Duke Nukem Manhatten Project include:
"- Updated to ZOOM Version 1.8."

I believe it's an AGS game, so you should be able to play it with ScummVM which may or may not help with any possible issues you have with that game.

No, I got a couple games from them, and never used any kind of client.

Thanks for the tip PixelBoy. Yes, ScummVM is AGS compatible (mostly) and that might work, however I already bought it on itch.io instead of GOG as there's just no way of telling in advance what GOG games are safe / bugged, and it was just one example of many. Whilst yet another "List of GOG offline installers with the unfixed Galaxy Timeout Bug" community spreadsheet keeping track of this would help, there comes a point (on top of missing features, outdated builds, 2nd class citizen lists, etc) where you just have to say "Enough is Enough". The whole DRM-Free shopping experience here certainly just shouldn't be this... exhausting... In fact I find it utterly absurd that it takes several times longer just to research whether a GOG offline installer game actually works properly offline without any "Galaxy degradation issues", looking up GOG reviews, game sub-forum comments and 2-3x community spreadsheets, etc, vs only 5-15 seconds to enter a serial key or apply a NoCD / Goldberg patch to a DRM'd disc / Steam game, and those versions still work *better* post DRM removal than GOG's Galaxified "DRM-Free" builds do out of the box...

I can get abandoned Starforce & SecuROM DRM'd disc games working flawlessly under W11 minus all DRM that startup lightning fast, yet GOG can't get their own GOG offline installers using their own API to startup normally without freezing up waiting for "approval" from their own client after 6 years of bug reports. I think what really gets to many of us isn't that mistakes are made / bugs exist, it's the underlying "We will continue to ignore absolutely everything wrong with the website and offline installers if it doesn't involve elevating Galaxy onto a mile-high pedestal". If they've stopped caring even in the slightest about their offline installers, then I just don't want to reward that attitude and throw money at the store anymore and rather than "Just Use Galaxy (tm)", from now on every game that can be bought elsewhere that runs (or can be made to run) DRM-Free and client-less, then I'll just buy them elsewhere by default.

Kudos for writing out he proper fix in a much more detailed manner than what I coughed up earlier. And yes itch is a very nice little site. I use it to give the devs a bit more money for certain games from time to time.

Glad to see the suggestions didn't make your computer start on fire and you got it working. Happy gaming!

You made the right decision buying the itch.io version as the developer actually confirmed the long startup delay on the GOG version in the game's sub-forum is due to "using Steam achievements in GOG games". It even comes bundled with a literal steam_api.dll file:-
https://www.gog.com/forum/the_castle/steam_apidll_problem/post2

Fun fact - If you add the GOG version of The Castle to ScummVM, it gets recognized as being the Steam version (that it actually is) due to all the SteamWorks code still active inside it. So even the ScummVM team can see "GOG Wrapper" games = GOG are now selling Steam games with Steam achievements inside them then passing them off as "GOG" games by putting a Galaxy translation wrapper / "GOG" marketing sticker over the top of it. Keeping track of what to avoid buying here is more work than actual work. :-(

Edit: Agree with this. GOG need to start fixing these problems, not just keep ignoring anything that isn't Galaxy.

Nope, no client.

That just means the ZOOM version of the game has been updated, and likely differs from other versions of the game.

And if it is still the case that only ZP is selling the game now, then the ZOOM version would be different to the original version of the game and different to the version that GOG used to sell. That meaning better support for latest Windows and perhaps bonus stuff etc. It doesn't likely mean anything negative, more likely positive.

In any case, my post wasn't about a client as such, but about the unnecessary DLLs included. If you are only using the Offline Installer version of a GOG game, where those DLLs especially cause issues, that should just simply not occur, and it is bad form by GOG that they do occur. We shouldn't have to turn to replacement DLLs provided by a third party (Goldberg) to fix the issues.