After downloading a game installer I noticed it gets rebranded as a GOG .exe, it wants to install the game into the "C:\GOG Games" directory, and Windows shows the program's "Publisher" as GOG. This bothers me as I was hoping it would be just like the original DVD/CD-ROM installer.

On top of that, the game's directories may be moved as well, not merging with the folder structure I already have. For example, S.T.A.L.K.E.R.: Call of Pripyat will have different locations it keeps your save games, depending on if you installed the Steam or GOG version.

All of this I mentioned I believe is commonplace with all or most GOG games.

So why can't the original installer or ISO be supplied, or simply the game files in a compressed folder so I can place them where I want (i.e. portable installation)?

I have pretty much all of my games on Steam but want to backup my library and have the DRM-free experience, but at this point it would seem better to dig around for the ISOs (or original disc installer) or use a crack for Steam DRM (seeing as how I've already paid for all the games).

This is such a non-issue.

Galaxy's default location for games is in Galaxy's own directory under Program Files (x86). It's not like you can't change that yourself.

Even retail installers had messy locations at times. It's not like you can't change that yourself.

Yes, and?

For a lot of games the original installer may not work at all on modern computers, like is often the case for 16bit installers from the Window 95/98 era. Then there are various versions of DRM, some of them would be installed during the original installation process, or the game ISOs would be useless since DRM asks for a original CD. Then there are various registry entries that installers make that (I think) can not be made by just extracting a compressed archive (though you can easily add them manually, but that just complicates things).

"C:\GOG Games? So,whats wrong with that?

I don't see why GOG has to rebrand every installed game as it's own, or even advertise its website through the installer, which can even be considered as adware. Neither of these instances are present on Steam.

The default directory the installers use that I mentioned seems to be nitpicked by others, so maybe I didn't word it right. That was just one smaller addition to the way the games are rebranded, my concern was the fact they are altered by GOG and don't offer a portable installation (i.e. without the GOG installer). Though, as another user pointed out, some games will need to create registry entries.

This brings me to my other concern: will the installer work across operation systems or is it platform specific? I see that as being the only reason they use their own installer, otherwise I may as well just download a specific installer or games files for my OS (i.e. Windows 7 64-bit).

I just don't see a point re-buying my game library here for backup, if the game's files directories are going to be moved around, meaning the configuration and saves directory (look up a game on PCGaming Wiki) not the installed location. And I could probably just find a way to remove Steam DRM for many older games.

On your library item, under the "Install game with Gog Galaxy" branded blue button, is the tab labelled: "Download offline backup game installers".

I believe this will solve your (solvable) problems. (Though, as antrad88 noted, vide supra, there are certain inalienable fixes that have to be performed on some older games to be able to run them in a modern OS. This has no impact on where you decide to place the offline executable installers, nor where you instruct the installer dialog to store the game folder. It does mean that Windoze is liable to save some game-related files in areas not immediately obvious, like gavesaves in the Documents folder under the name of the game folder, for instance.)

Edit: second batch of questions [1] Believe it or not, old games do not just "work", they need some customization to allow for, for example, non-existent CD media used for copyright authentication of the original game, or to move the game from where it would have been installed when originally released (in a previous version of Windoze or even DOS) that is not permitted (for the integrity of the OS), like the Programs folder.
This customization is value-added proprietary work (subsumed in the retail cost of the purchase) that they own.
[2] See my previous comment about OFFLINE BACKUP GAME INSTALLERS. There are different executables for different Operating Systems, like Apple and Linux as well as Windoze.
[3] "Just find[ing] a way to remove Steam DRM" is illegal. If that means anything to you, then obviously a legal alternative is meaningful, too.

Yes I am using the offline installer. For example the game S.T.A.L.K.E.R.: Call of Pripyat gives me the file "setup_stalker_cop_2.1.0.17.exe", though it is a GOG brand installer and advertises games through the installer. I tried using "innoextract" to simply get the files out, but I seemed to run into too many problems and couldn't get it to work. All it seemed to pull out was the many banners and images that GOG puts into the installer, useless stuff. Though I am also provided two other files with an identical name but appended with the .bin extension. I found though these be can unzipped, though I wasn't able to extract the game properly that way either.

As for where the game creates additional user folders, it is different with GOG and that's problematic and requires additional work when backing up those files. So I mentioned the Call of Pripyat game, here are the save directories for it:

Windows %PUBLIC%\Public Documents\S.T.A.L.K.E.R. - Call of Pripyat\savedgames\
GOG.com %USERPROFILE%\Documents\Stalker-COP\savedgames\

Since I already own them on Steam, I continue to play them there and want to use GOG to back them up. Though, if I ever decide to use the GOG backup copy, I will have to search for the new directory and restore my saves or user config there.

So, your problem is that you are unwilling to use the installer to install the game (wherever you wish, as selected by you in the installer at the point just before the installation), presumably because you don't want the invasion of Gog-curated advertising to ruin your installation pre-playing experience?

When I buy something I'd like to keep it forever. If the "law" had it's way, there wouldn't be GOG. Hence my problem with Steam and most digital platforms today, they "lease" the product/game to the customer, though in most people's minds they believe they "own" it. Product key games or older DOS games may have had some form of DRM, but could be backed up in their original form. Reverse-engineering a DVD to keep the ISO installer, etc. may be frowned-upon by corporations seeing as how this can be used to distribute it freely to others, but it still doesn't take away the fact that that person did pay for it. I am not advocating piracy, I would just like to own what I pay for as long as I want. It's copyright laws are designed so that people won't get to keep it for too long a period, since the publisher wants to resell the game again once most people have forgotten about it (as we know "remasters" are huge in the game industry).

At this point, I'm coming to realize the main issue is the game save/config directories created that are in different places, but the installer and game's rebranding is a little irksome. I've also noticed the GOG desktop icon and included game manual are different, the original one Steam provides look much better.

Alii aliud dicunt.

Most installers were licensed software products that the original publishers purchase licenses for. Those licenses are probably unavailable to GOG.

Also, many wouldn't work today. Or might install to nonworking locations.

in the old days, companies used to advertise other games images. Gog reflecting the old days, did the same with their installer. I like it. It's a nice touch.

The original installers often do not work in modern systems and GOG modifies the games for compatibility, often adding patches, DLL overrides, music fixes and - for older games - wraps emulators like DOSBox. The GOG installers also use better compression that what was available 20+ years ago, which helps both GOG (bandwidth costs) and you (storage costs, if you want to keep your own backup) and unlike older installers which were more often than not made up of thousands of files, GOG's installers are always the minimum files required for storage (single file for Linux and Mac, 4GB pieces for Windows - most likely to be FAT compatible).

The default location is C:\GOG Games most likely because a ton of games, especially older ones, need to modify their own folders (for save games, configurations, etc) and since Windows Vista with UAC it can be a PITA to do that in C:\Program Files - especially if you also need to modify those files (for mods, extra patches, etc).

Not all games need the above (especially newer ones) but obviously being consistent is a good thing.

GOG doesn't usually rebrand games. They rebrand the installer yes, as said above the original installer usually doesn't work for older games, or will have issues.

The directory (so installing to C:\GOG Games) you can change yourself. And for the desktop icons the original exe is in the games directory so you can just find that and right click and create a shortcut to that. They even have the original icons usually (though DOS games will not usually have an icon as most didn't have one.)

Most games will run fine from their original exe files (GOG sometime have a gog.exe file in there for some reason, so i'm assuming its just a wrapper of some sorts. Thats usually not needed.)

And if a game has gog.exe then the shortcut that GOG's installer creates will usually point to that rather than the original exe. Also its worth noting that GOG's shortcut path sometimes has some fixes in the target line of properties, sometimes you will need to add these to your shortcut to the original exe.