If they didn't split them, then others would complain that they can't download a 130GB game on their slow and flaky internet with a monthly download data cap.

Also, having several parts may allow you to download the game faster because many of the download servers seem to limit the download speed to e.g. 5 MBytes/sec per file. So if you download e.g. 4 parts in parallel, you download at 20 MBytes/sec instead, not 5 MBytes/sec.

If it bugs you too much, there are third-party tools where it downloads all the parts in one swoop.
Also a good point, I forgot about that.

Earlier GOG installers used to have also the first part as a bigger 4GB file (games that are below 4GB in size still have that, the whole installer is contained in one bigger exe file). When you wanted to install the game by double-clicking that 4GB .exe file, there would be a looooooooooooooooong pause before the installer was launched, apparently because Windows Defender or some other AV was scanning that 4GB exe file. Or was it calculating some digital signature or something, I don't know, but there was something causing a delay due to the size of the exe file. That is why the first part (the .exe) is nowadays much smaller (e.g. 2MB) so that the scan goes through much faster.

Now, think it that .exe file was 130GB instead, maybe you'd always need to wait 10 minutes before the installation starts...

I am always surprised when I read the recurring argument about slow Internet access. All the mainstream Web browsers that I can think of have been able to resume interrupted downloads for at least 15 years.

And using Firefox, I have never seen a single corrupted download. Not even once, in more than a decade.

Resume does not always work for me on various sites, not sure why. Also I recall having corrupted downloads in the past over flaky internet connections, e.g. many many years ago when downloading some GOG game installers in rural Thailand over a flaky mobile data connection.

Also it is possible some people still have e.g. monthly data caps so they want to download a big game in parts anyway, possibly even on various different places or computers, e.g. some of the files at their home, some at their work or the university or the public library...

I personally would be fine with either, everything in one big file or the current division to 4GB parts. I don't feel particularly strongly about either option, both have their advantages and drawbacks in certain situations. It helps that I can use gogrepoc so I don't have to click through all the files of Cyberpunk or Baldur's Gate 3.

EDIT: But I still wonder, what would happen if e.g. Cyberpunk or Baldur's Gate 3 was in one gigantic exe file? Would there be very long pause that IMHO happened already with 4GB GOG exe installers? So if it was in one big file, then it would have to be something else like a compressed zip or rar file... but then Windows doesn't support such by default, it only supports zip but isn't there some size restriction as well, ie. Windows zip supports only smaller zip files?

If I were the one to chose we would go with single file installers (as we already have for Linux), but the split ones do not really give me an extra headache so I have no big grudge against them.

It’s mostly that the arguments used to defend them always seem a bit strange to me, so I tend to stick with the most credible explanation I found: the usual lack of tech literacy from GOG.

Here I go with LGOGDownloader (directly provided by my OS), I guess they are both quite similar. I use it in unattended nightly tasks to automatically download updated installers that got released during the previous day.

For me, a Linux user, nothing would change but the number of files on my disk. I already extract the game data without executing the installers, so they can fill them with bloat and advertisement without affecting me.

For Windows users on the other hand I have no idea what would change with such merged installers. Last time I used it was more than 15 years ago, so most of my Windows knowledge is most probably obsolete ;)

I have tried lgogdownloader in the past, and on the surface they seem similar tools for a similar purpose. I've stuck to gogrepoc as I am more familiar with its capabilities and what it actually does, and it works without issues on any device that can run python (Windows, Linux, Raspberry Pi etc.). It would seem for Windows lgogdownloader needs some hoops to jump through.

gogrepoc is also quite portable, ie. you don't need to install it to every computer where you want to use it, as long as said computer can run python and has the needed modules (so yeah you still need to do some "python preparation" anyway, at least to confirm those modules are installed on top of python...). I actually have the gogrepoc.py at the root directory of the USB hard drive where I keep my GOG offline installers, and I run the script from there, regardless of to which computer I have connected the USB drive. I even have separate .sh and .bat files that are run either on Linux or Windows, respectively (the scripts simply run all the four gogrepoc commands in succession: update, download, clean, verify).

Also because it is readable python code, I can myself make minor changes to it for my own needs, like because its hard drive space preallocation seems to glitch (=not work, timeout) if one runs the script on a Linux machine and the target partition is NTFS (e.g. an external USB drive), I can pretty easily comment out the lines in the code where the preallocation is performed. Wasn't hard even with my limited python knowledge.
 
It at least used to be that with the installers where the .exe file was several gigabytes, there was a quite long pause (like 30 seconds or even longer) before the installer would start, after double-clicking the installer. I don't recall if it was confirmed what was the reason, I suspect it is either antivirus scanning the big exe file before allowing it to run, or some digital signature checking or whatever that takes longer for bigger executables.

To my understanding that is why GOG changed the installers, at least those which would be in several parts anyway (ie. over 4GB), that the first part, the .exe file, is small (usually it seems to be around 1-2 MB, sometimes even less).

Naturally, that doesn't explain why the .bin files couldn't be one gigantic file, so all those big games would be in two parts (not one part or dozens of parts); there would be one small .exe file, and one gigantic .bin file.

What someone said about it being some known restriction in innosetup, that sounds the most plausible explanation at this point. Not sure what would be a better option for Windows offline installers.

I've earlier suggested I personally preferred if the "installers" were mere .zip or 7-zip compressed files which I manually decompress to some folder and run the game from there (Humble Store has some games like that), but I realized now it would have several issues too:

1. You would most probably have to install some third-party tools to decompress such huge files because (IIRC) the basic Windows zip support has some pretty low size restriction (maybe it was 4GB).

2. Making a self-extracting .exe file would probably have the same "pause" issue of big .exe files, ie. Windows or AV would scan the .exe file before allowing it to execute (decompress). But at least this option would not require installing a separate utility for the extraction, I guess?

3. Overall that would confuse newbies who'd like to try the offline installers, having to instruct them how to install some third-party software (which they might not be even able to install due to lacking admin rights, or just don't feel comfortable installing unknown utilities just because someone tells them to etc.).

Not when it comes to the physical disc itself. As you know the discs burn from the inner spindle to the outer edge first, so the amount of radial room required for the data is lessened as you go further out. Under-utilizing the disc leaves a nice neat (and rather small) gap on the outer edge of the disc - like I said, the edge which on average suffers the most potential damage from accidents when dropping, careless disc insertion, folder storage abrasion, and outer edge rot (human wear-and-tear).

When I used to burn discs I wouldn't use the entire surface for those very reasons. I divided the data up into equal sizes and always left an edge "gap".

Besides, who's being "punished"? Those who turn their noses up at the old fuddy-duddys who like the 4GB file sizes because the sizing isn't convenient for them are more likely to be using a more convenient way of downloading their games anyway, right? Like Galaxy - which allows you to download all these chunks with one easy click. Right now GOG has given you an option with offline installers: download the files individually via browser, or download them en-masse with Galaxy.

If you want to bring up Galaxy not being available for Linux users, I agree, that's totally not fair. But that's a side issue to this.

You want to know who REALLY are being punished right now? The browser downloaders in certain regions who are getting sh*t speeds because GOG is cost-cutting with its CDNs. Imagine downloading a singular 120GB exe installer and maxing out at 300Kbps. Nice, huh? Even for a 4GB block it's damn painful.
Can we resume? Yes, for the most part. Until the token expires, of course. And we also have to be sitting at our PCs to manually resume a timed out link as well while the data trickles in.

Normally I have decent speeds, but since GOG has decided that the Oceania region isn't worth a damn, the 4GB sizes have been extra useful because I can juggle my download times and can pick and choose when to suffer through a pre-ADSL download session when I want to.

Question: What if GOG used torrents instead?

They won't use torrents because:

1)It will easily get of out hand and people who didn't pay would easily get the games.

2) They cannot force clients to sacrifice their disk space and internet to become the seeds.

3)It can be used by sinister clients to distribute viruses and other files under the disguise of game.

Well I dont see how its a "pain" ? The interface is somewhat tough to figure out at first, but once you get that working, its fine.

What I wished is that you could get certain old versions of games.

Like with Vampire Bloodlines I really just want to have the original version as it was in the end (i.e. with the original patches). I can apply the fanmade patch just fine by myself. Dont really need new versions of that.

And with No Man's Sky I really wished I had the last pre-4 version offered because they changed how inventories worked after that, and my old games are basically unplayable now, i.e. I refuse to play them with new inventories and instead rather started building up everything under the new rules.

I mean they could just allow to use the Galaxy client to download the offline versions. Then all these points are moot.

Galaxy already can download all the 4GB-max offline installer packages for a game in one go.

This doesn't seem to have stopped Humble from offering them for a decade now.

Nice !

1) Is that true? If GOG acts as a private tracker for the files, can't they decide who can download the file and who can't?

That's a genuine question, I am unsure if a private tracker can easily control that. However, Humble Store has used bittorrent downloads for their DRM-free installers for years. If there was an issue that anyone could tap in and download any of the games without paying for them, I presume they wouldn't use the system.

2) It could be optional, so those who want to use it (e.g. because it offers them faster download speeds than direct downloads, and/or because it makes them feel good they can help the poor Oceanian GOG users to get their paid games faster), could do so.

For instance, I wouldn't mind let e.g. my Raspberry Pi 4 to act as a seeder 24/7 for the >2600 GOG games that I have, as part of that official GOG bittorrent network, as long as I knew the downloads would end up only to legit users who have paid for the games (GOG's duty to make sure only legit users can initiate the downloads).

That's the case at the Humble Store, you can either use a direct browser download, or use the bittorrent download option.

3) How? I don't know the bittorrent protocol but I presume it does check the checksums of downloaded parts over and over again, to make sure it gets a non-corrupted download.

Since GOG itself would be the tracker and the original seeder, their version of the download would be the correct one that everyone uses. I don't know if there really is some known vulnerability in bittorrent where one can inject malicious changed code to downloads, but I presume it should be pretty safe as it is so widely used also for non-pirate downloads.

Anyway, I am not expecting GOG to invest resources on such option since they have pulled resources from other side tasks as well like Linux support etc. I'd like to be positively surprised though, maybe it is a small task to add an optional bittorrent download option with GOG as the private tracker?

This is pretty much the key thing here.

I remember trying to download 200mb in the late 1990s using a 52kbps dialup connection. It took 12 hours and I ended up having to try two or three times. Trying to download a modern game on anything that isn't Fibre to the Premises is analogous to this.

In general, if a user can't put up with downloading 20 files or using a script to do it for you, then it kind of feels like Galaxy was designed for him...