Long story short, I have a monthly download cap here, and I'm going abroad from 20 to 30 December. When I go, I'm bringing my small notebook with me, and could download the larger Steam and GoG games I bought in the sales that have just gone by (and anything I pick up in the winter sale), or at least the priority ones. Said notebook is a lot smaller than this laptop which I play games on. A hell of a lot smaller.

When I get back, will I be able to slap the installers / parts (the games are Witcher 1 and 2 and Brutal Legend, it's my first time getting GOG games with installers in multiple parts, kinda shocked to see they are .exe files and not .rars unzipping into one exe) on a USB device and put them on my games laptop, then sign in to gog and verify or somesuch?

As an aside, I think I'd be better off using the GoG downloader as I can presumably queue downloads overnight then - but I'd like to know, does the downloader simply download the same installer files that you get from the library? It'd be pointless to install them on the notebook. It's just my word processor / handy storage lappy.

Thanks in advance!

Of course you can move your GOG installers through USB (provided that your USB has enough size). The difference is that you don't need internet to run those GOG installers once they have been downloaded.

Once you donwloaded the installers you can just copy them to your USB or to other computers and use them there to install the games. There is no need to log in on this site or anywhere else, you don't even need internet ;-)
And in regards of the downloader, the file you receive with is is the same installer file as the one with the browser, it is just there for convenience since you can queue the downloads and also the download speed is normally faster because of parallel downloading :-)

(by the way, welcome to gog)

Most of my GOG games were downloaded from another computer and transferred using USB. The installers are just files, and not tied to the computer you downloaded them on in any way.

Cheers for your help all - I knew GoG was 'DRM-free' but I would have never guessed it would have been to this extent! Thanks, you've made the coming month much, much easier :)

The files from the GOG Downloader and the manual ones are the same, If you want to download let's say part 1 and 2 of a game manually and later get part 3 and 4 with the downloader, then you can. Just put them in the same folder when installing :-)

Depending on your USB size, if you want to avoid going back and forth between computers, you can simply transfer the files using your network.

It's kinda heartwarming to see someone who is this positively surprised by actual "DRM free" and who will truly benefit from it.

Agreed, I think that maybe because some people have no idea what DRM is and the benefits that DRM-Free can bring.

Yep.

When you have the habit of playing on a laptop, far away from any connection, a GOG account and a USB stick are the best thing to have. :)

The reason why you'd move the installers instead of the game folder is registry edits made on the install of your game so that the computer knows where to find everything from the game after it's installed.

I'd add a bit to what others said before:

You get the same files with the Downloader client as with just using your browser to download the files, but using the Downloader is probably still preferable because it nicely creates appropriately named subfolders for all your downloaded GOG installers, something that you'd have to do manually if using the web browser download, or download all your GOG installer files and extra stuff into one folder (=messy!). So the Downloader organizes the installers for you quite nicely into separate subfolders, containing everything relevant to that game only.

You also need to click much less with the Downloader with the bigger installers, as one click will add all the relevant installer parts to the download queue (and another click all the extras, if you want to download them too). With the browser download, you'd have to click on each item separately, which can mean much more clicks, depending how many games you want to download.

The Downloader client does have some sort of integrity check, but I'm unsure if it is quite foolproof, because there have been a couple of cases before where I've found out later that some of my earlier downloaded GOG installers were corrupted. Naturally I can't tell for sure if they were already corrupted during the download, or only got corrupted later when I e.g. copied them to/from an USB hard drive etc., can't prove either way I guess.

So if you want to be sure, it might be a good idea to check your downloaded installers' integrity after you have downloaded them. The procedure to do this depends whether the game is smaller (=the installer is in one executable file), or bigger (the installer is divided into several files):

Small game (one setup file):
- right click on the setup file (e.g. setup_gorky17_2.0.0.3.exe, you might not see the ".exe" suffix if your Windows is told to hide the suffixes of files, which I've always found an extremely stupid thing in Windows)
- Properties
- Digital Signatures tab
- Click on the item on the Signature list
- Click on Details
- Wait a bit (how long, depends on the size of the exe file). If it says the digital signature is OK, then the installer integrity is ok.

Big game (setup file divided into several files):
- When you start the game installation, go to the installation Options, and tell it to check the integrity of the installer, before installing the game (this may be enabled by default, but better to check it). Unfortunately this will also install the game if the integrity is ok, I don't think it gives you an option to exit the installer after the integrity check, before the actual game installation starts.

Old GOG installers were better in this regard IMHO, they all had an integrity check in the beginning when you double-clicked the installer, and you could cancel the installer after that so that it would not install anything, if your meaning was just to check the integrity of the installer.

I'm unsure if someone keeps an up to date list of GOG installer checksums, so you could check the files against them without the steps above.

Plus you usually want to launch the games through the shortcuts which often include some additional step that is necessary to make the game work properly. I think these days GOG always also includes them in the game's folder but I'm not sure it's true for each game by now.

If it was anything less, it wouldn't have been DRM-free. (Well, allright, copying the installed game would have satisfied as well, depending on exactly how you define the term.)