The current installers are fine, and good enough.
At least they work, and that is good enough for me.

To hell with maximum optimizations, I am not fully optimized myself either, some fat in the belly and I'd like to have a bigger reach for my arms if I were to consider a professional boxing career or joining an orangutan community in an Asian rainforest.

As explained before, the reason why the GOG installers are compressed twice is most probably so that they can effortlessly create the installers from the original Galaxy-ready game files, without consuming time and energy to always repackage everything heavily, when a small update appears. That in itself is also optimization of the GOG installer generation.

What a sad world where Audrey Tautou makes better installers than paid professionals.

Linux installers though, a mere afterthought for GOG and most people on GOG, are NOT obfuscated or doubly compressed. Which goes to show you simplicity is possible if you just get the "dirty paws" of your optional client away from the offline installers.

Any argument that this benefits automation in any way is moot, because automation could simply be changed to package the installer after the content streams have been decompressed (post-delta).

My only complaint here is about installation speed. Even on a fast SSD it takes much too long to install a Windows game, mostly because of the problems mentioned above. I'd even suggest using zstd for its blazingly fast decompression speed, but it's not the compression algorithm that's really at fault here, it's the packaging. I kind of miss the days of simple 7zip compressed installers, even if those were also slow as hell... at least they took up much less space.

Or girlcott... personcott, really. Let's make it an inclusive type of cott with muti-colored torches and pitchforks :P. A sign of the times, as they say.

Glowsticks and pacifiers, for that real early 2000s raver feel. Make sure someone shaves their head and dyes their hair some loud color.

The ideal is a timeless immortal sneedcott.

I wrote some installers for Windows back in day with nsis and innosetup, back then there were free tools to track what was changed on your system, I presume it is now similar. On Linux its even easier.

So, write your own installers, ideally of a zip file with a reg file if its needed. Past certain size customer opinions go off the radar of the commercial companies. Thats why modding scene exists, thats why the best software is written by small groups. Sapitalism cucks, this is systematic thing - look at HB, in the beginning their installers were drm-free consisting of one archive, and as they grew larger they devolved into irrelevancy. And thats just company-centric view, without global winds. You think there are exceptions? Fileserver is your friend.

LZIP is Open Source, a robust compression algorithm, that can be as fast as ZIP but better compress and can be not ultra-CPU-hungry/RAM-hungry (can work on Raspberry Pi Zero W), can be made so files can be appended or removed ("--no-solid" in the "tarlz" package) at any time, offers high compression if desired (like 7-Zip/XZ), can be extractable standalone by any user with an Open Source LZIP extractor, and most importantly and uniquely is capable to recover from Bit Rot with zero additional cost in space unlike RARs' recovery records.

It might be a better idea to use this than the crazy monstrosity that GOG is currently doing.

Are you a bot?

Excuse me, what's wrong with you?!

What do you expect a human being to answer and why do you ask such odd questions? If I answer yes, just for the sake of absurdity, you will think I am a bot, if I answer no, you will still insensitively think I am a bot (and that's offensive to even assume a human as the soulless machine, honestly). So what the point of this? Let's smart for a minute, in the digital realm the identity of somebody is less important that the points they make on a topic, the same way a book's cover is not as important as what's inside. If you want to go wild, look up what GPT-3 is and accept the reality of our life and the fact that this technology at its full wraith means the question is no longer useful.

In short, please never bother anybody with this kind of odd questions, seriously, this is pointlessly silly. If you internally iterate on a constant basis about it for no good reason, there are better ways of finding the answer, for example by interactions that only a human can do well (for now).

In any case, this is off-topic and I hope GOG staff will remove yours and this very message.

They have another flaw which really isn't GOGs fault however - or at least only partially:

The UI system they use is bugged on Windows 11, the installers open in the background, they don't get the focus after you confirm the elevated rights.

I encountered this bug with the Windows 11 context menu as well, if the new API is used to add commands to the new menu. As long as you actually use the new menu, it's fine. But if you display the old one (by using keyboard or switching to "more options") and execute the very same command there, the program will be opened in the background.
This has been around for about a year now, no fix. Yes, it's not GOGs fault, but they might want to switch to a different UI at some point.

The use of the temp folder most likely outweights this problem :)

In my view all problems on all the systems, big or small, are to be noticed. Please do write if something else on Windows 11 does not work with GOG installers. Why? Only knowing a problem's existence can help to fix it at some point, a silenced problem is very unlikely to be addressed.

The installers work just fine, they just don't get the focus, that's all.

ps: And it's also not happening every time. I started the same installer now 10 times in a row, in 4 cases it did not get the focus.
I assume, it has something to do with the loading time. When it opened quickly (I have them on a network drive, so it's a bit slower), it would display correctly. When it took a second for the icon to appear in the task bar, it's in the background.

It was always in the background if I tried different installers each time. That's why I think it's connected to cached data and the loading time.

Unfortunately, the problem still exists. And since the Galaxy interface has also been in version 2.0 for ages, I wonder whether GOG still has the ambition to optimize its software. The Galaxy overlay is also really horrible, it's extremely slow and has hardly any useful functions.
Since all this has been the case for several years now, I'm worried that a new version of Windows will be released at some point or that people might want to switch to Linux after all. Steam is trying something in this direction, but I just don't see any progress with GOG.

I don't want to be stuck with offline installers in a couple of years that no longer work properly on new operating systems.

I would therefore like to ask the GOG programmers to take the existence of Windows 11 seriously, to improve compatibility and to bear in mind that Windows 10 will not be supported forever and that Windows 12 may already be in the starting blocks.
GOG urgently needs a perspective that is communicated accordingly.

A car with little paint is difficult to polish.