Maybe the size difference comes from CD vs DVD? Because, as I recall, GOG has been offering three different versions of Riven in the past:

1. The CD version release.
2. The DVD version release (which I presume is bigger than the CD version; I will check it later).
3. The ScummVM version (which might be using the data from the DVD version?).

Nowadays GOG offers only the ScummVM version, as it works fine with Windows 10, while the other two had issues I believe.

I have the CD and DVD (GOG) version installers saved to my archives as well, I'll try to remember to check their sizes...

2.7GB is about right for the 5-CD version. 6.6GB is likely the DVD version. The difference is the bitrate of the videos, you won't see a difference in the stills.

The most recent change came about when Cyan released the 25th Anniversary editions - ScummVM is now the "official" way of running the 25th Anniversary versions. It's possible the videos included now are even less compressed than the DVD version.

As for the aspect ratio, the stretching in the old version is a sign of not having set the aspect ratio settings correctly in your video card control software, nothing to do with the game specifically. ScummVM is preventing the stretching itself by scaling the game.

I'm so glad I never use Galaxy.

I'd be okay with that, but I guess GOG decided it's not worth spending the time to do that. Nothing I can do about that choice obviously.

If an original release worked on XP and GOG's doesn't, you could consider an "abandonware" site if necessary.

Ironically some abandonware sites point to gog.com

I went to look at the files and it would appear the size increase is because it installs all the different language packs at least for the offline installer.

Strangely the requirements still say it works on XP

This is the exact problem. They have added unneeded api reliance to working games.
I bought the whole series of Fate games only to find they no longer run on my chosen machine that I used to play them on. (No I'm not going to lug around a huge win10 machine when I have plenty of safe, working, lightweight xp laptops to use)

Some developers still program new games to run on xp (Such as Oniken), GOG is the only platform that doesn't support xp for these games.

If they changed a Mac game so it only worked on Linux because "there are less Mac users" they would lose many customers so why is xp different?
Win95 games should run on win95, DOS on DOS etc:
It's not like we're buying PS4 game to play on an Xbox.

I, for one, am not going to buying another game from GOG until they remove the Galaxy.dll from one Galaxy games
I have lost all trust and respect in GOG as a company.

You've necroed a thread, but what you are saying is both important and troubling.

The existence and requirement of the Galaxy.dll is very worrying. You could even call it a form of DRM, that limits where you can install a game. While I can understand it being a requirement for Galaxy, it should not be a requirement beyond that, and certainly not with Offline Installers.

Are we all being taken for a ride, had the wool pulled over our eyes?
I seriously hope not.

There has been a lot of threads on this. There are various levels. Some newer games require galaxy.dll, the same way they require steam.dll, and will not run without those. Most other games have had this retrofitted to some degree. Recently Titan quest had this included in an erroneous version, and it would not run without that dll, they did however fix it. Some games have it present, in case galaxy is installed so it can do achievements and such like, but it can be removed.
I haven’t done a complete check of all games however, so it’s broad strokes here. But yes, one day you will be looking for replacement cracks for galaxy.dll for your games. It’s all so it’s “easy” for those who only use galaxy, the question then is why would they even want offline installers, most don’t even know it exists.

Yep, I have read at least one other thread warning about the issue, where it was discussed in some detail.

Why? Galaxy itself isn't required for the games, why would you replace the dll?

Well for functionality - multiplayer/achievements, but more so if the actual game requires the dll and for some reason that dll no longer works. For instance in the Titan quest example, the dll has to be present the game refuses to run at all without all the steam gog dlls in place. Now that was an error and has been fixed, however it clearly shows what will happen to all these games that these things are being built into. The constant evolving os system could effectively break that at any time (see securom removal by by windows, or change of 16 bit to 32bit for some installers), rendering a game which would run correctly without no longer functioning. True it’s probably not the biggest issue here (heck it would struggle to make the top 10 currently) but it’s worth thinking about as all installers have now been “updated” for this, and the galaxified installer setup, and in some cases they have broken it, or removed content.

In context of the thread, adding galaxy.dll's (that have already swollen in size 10x since Galaxy 1.0) may introduce unwanted dependencies that break compatibility with older software / OS's. Eg, Fallout New Vegas used to work on Windows XP. Then it stopped working the day GOG added Galaxy integration to it. You know what the absurd fix was? To have to replace the GOG dll with a renamed Steam one... The usual "But GOG is about old games on new OS's, not old OS's" stuff aside, the whole point of DRM-Free offline installers in general was supposed to be about a reduction of client based BS rather than an increase of it:-
https://www.gog.com/forum/general/good_news_galaxydll_breaks_xpcompatibility_in_good_old_games/page1
https://www.gog.com/forum/fallout_series/fallout_new_vegas_windows_xp_fix_for_gogs_package

So for the sake of your argument, you want to ignore that: XP is out of date, obsolete and beyond its useful life; that GOG has always wanted to bring classic games to modern systems as their standard; and that Galaxy is not required at all for any of those games.

If you must discard so many points of the discussion to make your point, perhaps your point is the wrong one to make.
It's like fighting a battle and telling the opponent, "for me to have a chance at winning, you must ignore all these glaring weaknesses and only attack my strongest fortress head on."

The whole point of DRM-Free is being able to play your games without any interference from some entity stopping you from doing so. People seem to think it means their old games should install on their original systems. Why not have DOS based installers, or Amiga based installers then? How far back are we going? Understaffed GOG is going to double/triple the amount of support requests and achival/testing work for what? To please 0.004% of the audience?

I'm ignoring nothing. I know full well XP is out of support. "But, but, but x OS is out of date so we should break what we want" is a lame cop-out excuse that tries too hard to ignore that there's a world of difference between a game that stops working due to natural and unavoidable reasons (eg, Win 3.1 16-bit games stopped working on 64-bit OS's due to NTVDM being removed from 64-bit Windows) vs a game that actually works fine by itself but arbitrarily stops working due to middleman vendors adding their own unwanted API's to their "digital cellophane" wrapper it comes packaged in that in turn add client based dependencies (that literally no-one asked for in client-free offline installers).

People can and do build "retro rigs" or on alternative hardware / OS's (Raspberry Pi's, old laptops, etc), and there's nothing wrong with that. Unlike some here, I'm not going to dictate what someone can / cannot use. Likewise using your logic, it would be perfectly fine if GOG intentionally broke the ability to play every game on the store under W10 on 15th Oct 2025 via Galaxy 3.0, even if W10 market share was +75% or so, then yelled "ur all wrong because W11". I disagree. As the founder of GOG once said "Paying customers should not be treated worse than pirates", and yet that's ironically the very same situation this introduces when the obsessive need to put Galaxy dll's in offline installers (people deliberately use because they don't want Galaxy) breaks things whilst a ripped ISO of a retail disk version of same game continues to work fine...