I'm not complaining, but noticed today that when I installed Avalon-2 that was bought straight from Spiderweb, it totalled 164mg on my SSD. Then when I looked at my Galaxy install of the exact same game, it was taking up 1.2Gb.
Wow that a lot of wasted space doing what exactly?

You count up that wasted space if say, you have 30 games install on Galaxy.

I believe you, still it would be interesting to see a screenshot of that game folder's size of 1.2 Gb.

Must be that super-massive black hole at its center... jokes aside, yes, Galaxy managed games can take up more space than the same games deployed using offline installers. If you're very space conscious you still (luckily) have the option of using only offline installers and no Galaxy, though that will mean no automated patching, cloud saves, multiplayer for some games, achievements and so on.

Yet 164mb vs 1.2gb seems too much a increase.

I had 1GB of log files recently from systemd. I think its a cache-cake: generations over generations of cache and logs, each backed up for security. I think utility like sequoia-view still works on windows (since galaxy is windows-only, I assume you use windows)?

I was afraid the thread was about Galaxy inefficiently rewriting on SSD, which would eventually end up killing the drive.

I don't have a problem with games taking more space, as long as it's just an overhead issue, The 164MB vs 1.2GB, if true, must be an extreme case, which would be meaningless if a 50GB installation were to reach 51GB.

As it stands, I'm inclined to believe there's something wrong with the installation or with the way OP interpreted what he was actually seeing. Some screenshots should clear everything up.

I'm currently playing Prehistorik 2 and Dangerous Dave, installed via Galaxy, which shouldn't occupy more than 10-20MB each. I'll report how much SSD space they actually take, once I get home.

Galaxy isn't Windows-only, it also exists for macOS. Still, Windows is a reasonable assumption, since it accounts for the vast majority of GOG users.

Don't know why your folder is so big... Does this game have the save files in the install folder? I just installed it and it's 170MB on my hard drive, installed from Galaxy. See my attachment...

On a side note, if you measure in Mb instead of MB, it is 1.3Gb, but that's the exact same size... Maybe it's a confusion of measuring units?

Sorry, my error it was 1.2MB and not GB. It's okay, I am due a appointment at the opticians.

I thought this was going to be a long, vicious Galaxy thread and refilled my coffee for the fireworks. Just an honest mistake, no harm done.

Probably because Galaxy downloads the game's redistributables. I noticed that yesterday when aborting an update for Ys Origin: a _redist folder was inside the !temp folder created by Galaxy in the game's directory, and that had a couple of redists lurking there. Of course they also take up plenty of precious space.

It certainly does in this case. I don't want to start another ethical debate here, but in principle when using any game client you should expect it to take extra space (as much as it needs) to store roll-back data, cache certain stuff etc. Expecting it to store all this extra stuff under a certain amount is certainly reasonable, but not always guaranteed to happen.

Glad to hear that, but anyway, this sort of stuff is not unheard of and can happen from time to time. I'll leave regular Galaxy users to comment on what can be done about it since I'm a clueless Galaxy-free entity (I live in subspace).