Probably achievements/cloud saves etc related. But all games should work normally without Galaxy. Else you should contact support about it.

It's understandable that for the file size increase of undesired functionality that one might prefer to not have to download the excess in absolute terms. In relative and practical terms in many but perhaps not all cases, the increased file sizes are negligible in the grand scheme of things with today's storage sizes, and providing a single installer that works for everyone rather than maintaining a potentially ever growing matrix of installer options for people to drill down and pick a wide variety of individual files that get included in the archive though. It just doesn't scale well in practical terms. So to provide new features sometimes requires a bit of file size growth.

Having said that, when GOG started adding the entire Galaxy client to every single game download that was way overboard as the extra overhead was quite large and per-game with massive duplication across everyone's entire collection. In that case I had to agree that this was a very poor choice by GOG, however I don't think they had any malicious or nefarious intentions behind it, rather it was just poorly thought out and executed. I was kind of surprised when they announced they would provide dual options for download for people later on as the extra overhead of doing so doesn't come for free, but nonetheless it was a very generous compromise they made to try to make everyone happy and an acknowledgement that the problem was big enough and affected enough people to be worthwhile coming to that compromise.

40MB increase in size does seem large for mere cloud storage feature enhancement though. Has anyone drilled down to figure out what is consuming that much space? It'd be curious to see if it is data files included with the games, or bloat of the installer itself, such as a bunch of game card graphics to advertise games during install or whatever. Perhaps a pattern could be identified and a more efficient means instituted to reduce the overhead if it isn't necessary.

I myself use and like Galaxy, however I also download all of the standalone installers and definitely don't want a full Galaxy client included in them and glad we have that option. I'm ok with GOG adding functionality like cloud saves and other enhancements in the future but would like to see them optimize the way they do things and avoid adding unnecessary bloat to new features whenever possible. If a new feature requires something and there's no better way to do it and it is justified then fine, but if it's done in an unoptimized bloated way I'd be inclined to give them some heck about it too. :)

One thing I really don't want to see GOG do is provide a large number of download options for various niche use cases though. That wastes their resources and makes things more confusing for the average person as to which thing to download and I'm sure that's a situation they want to avoid as it could easily cause an increase in support inquiries, game returns and dissatisfaction. I think they need to be careful about finding the right balance in catering to some of our collective niche desires and not making the overall end user experience over complicated with a matrix of many options for downloads etc. that result in a confusing mess.

I am legit interested in what that 40MB file size increase is caused by and if it is common with many games or not. I haven't done a full library GOG game archive download sync for a long time now and want to do one in the near future. I'm hoping my library archives don't triple in size without any substantial benefit. :)

^ The "custom build" is the GOG-only Galaxy one though. Surely the most common sense advantage for DRM-Free stores right from the start should have been to promote the ability of the devs to effortlessly reuse the same "clean" build of the compiled game to all DRM-Free stores (Humble, GOG, itch, etc) without needing to be re-compiled / re-built around store-specific clients each time. I'm genuinely amazed at how much "make-work" GOG creates for itself trying to "out-Steam, Steam", when it's already painfully obvious that developers have decided re-coding all Steam Achievements just for Galaxy is too much effort just for 15% of sales that GOG makes compared to Steam, and when most people who care about social achievement bragging tend to choose the site with the largest audience to brag to (Steam).

If even 1/3rd of those 15% of GOG customers care about GOG achievements, you're talking all that re-creation work just for 1 sale in 20 on a market whole, which is even more niche than why people buy the GOG version for stable offline installers in the first place. It's also completely at odds with how game development works in general - devs will typically code for Steam as a primary platform then when finished, they offer bug fixes / support for a short time and then swiftly move onto the next game. Barely 5% will re-port the same game to other stores custom rewriting everything for it, 15% will simply send it minus the extra work (missing achievements, etc), and 80% of steam games don't come to GOG at all. That's why despite GOG's aggressive Galaxy push, the entire store is filled with almost 1,000 games with missing achievements, missing Steam Workshop integration, etc, precisely because even the devs who do like GOG just don't want to spend money / time "reinventing the wheel" per store.

As I commented on the Telemetry thread yesterday, galaxy.dll's have already bloated out from 3.6MB (2015 games) to 13.2MB (2019 games). Today they have extra support files (GalaxyCSharp.dll, etc) and on top of that they seem to get replicated in sub-folders (eg, for Unity Engine games galaxy*.dll in the "base folder" are often replicated under Data\Managed and Data\Plugins folders so that it already exceeds +30-40MB). Given the file sizes have already consistently doubled every 2 years, I can easily see how that's going to end up by 2025 - the same place we were at when we had +150MB of Galaxy installer itself embedded, and it's going to look just as silly in small lightweight games.

Just adding some thoughts from another thread:
one of the main issues I see with it, apart from size, is that it is adding extra requirements to games. Take for instance years back, when we had games which had additional components like securom (not saying this is drm or anything like it, just that these components were required) but it all worked fine. Come forward some years and M$ in their wisdom block those components. This meant having to go to dodgy websites downloading nocd and other patches to enable your product to work again. Jump forward to the present day where games which work fine now have this additional requirements which may in future break. Are we happy to go back to downloading dodgy files to patch this? Maybe we will need SteamEmu and GalaxyEmu in future to run things.

If people want new features ie: achievements, cloud saves etc, you have to provide at least a stub implementation for them. No way around it.

Yeah, the question is simply whether it correctly handles not being able to find Galaxy. As long as those API implementations handle standalone use seamlessly then I have no issue with bits of Galaxy API ending up in standalone builds. It's only a problem if people cock the implementation up in a way that presents problems when Galaxy isn't present/running.

Thankfully GOG has no history of cocking things up...
And if people want those things, then there is that big blue button (/front page banner/link in every item on the website/default installer etc.) through which users can get said things. This does not mean that offline installers, of which most users do not even know exist, also have to not include all this and be tied to it, but to actively go back and re-release new installers with this new requirement embedded in games which did not before have it.
Effectively everyone is now using galaxy, it’s only wether you actually use their front end or not which is the difference.

Nobody will release two different versions of their game just to cater to one crowd or the other. So they will usually have the code there but not working for those who don't have Galaxy installed.

You can't expect developers to put in double the effort vs Steam just to have their games released here. That's a sure way to loose them.

I can’t actually check, but are you saying that dungeon keeper off steam requires steam.dll? Just trying to equate the two here. From what I understand, if you buy a drm free game from steam, then you should be able to package it up and take it away. Is that because there is an inert, but required dll?

End of the day though, isn’t that the point of having two different stores, to cater for two different groups of people?

Yes, likely it will have a dll if it uses the features while running in steam.

For big devs maybe it's not a problem but for a small developer if you add for each release an extra amount of work (and that maybe even twice the effort than steam), then they will snub you because they make like 90% of their revenue off steam.

There is a reason why Galaxy related files are in the offline installers even in games that work just fine without them: some people use the Galaxy client for your usual feature set, except instead of downloading games from Galaxy they download the offline installers. The files being present in the installers means the games are instantly compatible with Galaxy and thus features like achievements are available right away without any additional setups or downloads.

Those are my two cents for now.

This is an underrated and important point that I hope doesn't fly under the radar. Generally speaking, DRM can be seen as an extra, unnecessary step (but for the "necessity" of publishers/devs/stores requiring it, of course).

If there is something in the implementation or client components that are packed in with DRM-free offline installers, that is troubling for the future, at least for those of us who care about game preservation.

One could very well point out that, regardless of a client, a game itself might contain components no longer supported on a future OS. True. However, the inclusion of additional components, like client features, would be "an extra, unnecessary step".

Yes, and if you have Galaxy installed it will default to launch through that, even if you downloaded the "offline installer."

I've read before that the vast majority of the GOG audience use Galaxy. Also it's pretty obvious the vast majority of PC gamers use clients with Steam, Origin, Epic, Uplay, Battle.net, etc. At the end of the day people like me who wish to avoid clients need to undertstand that they're a small niche and the vast, vast majority of gamers want the client experience. GOG is continuing to provide the no client option, and have promised they will for the foreseeable future, but we need to always try and understand we're not the target market, even on here. There's a reason Galaxy 2.0 is the platform's current big push.

Just installed two games recently with offline installers, downloaded during or after the winter sale. If you mean the "Launch" button on the installer, that does lead to Galaxy starting up the game in my experience, but the shortcuts point to the games themselves. I've just verified.

It's another matter if you update a game through Galaxy. I haven't checked what Galaxy does if the game had existing start menu entries/desktop shortcuts, but a couple of games I have just updated now do have Galaxy-based shortcuts. So yeah, it's an inconsistent mess that I wish GOG would address (with options of course).