Amen.

I turn UAC off as well. All it's ever done for me is annoy the hell out of me.

They need the rights, because most of the GOG games are so old, that they were coded before the "good practices in software security" were a common thing in software design. Now days most games take account that the use of the game doesn't need admin rights, but for old games that really wasn't an issue, as the coders could pretty much do what they wanted with older windows versions. This translates poorly in moders OS's, which take security more seriously than Windows 95 for an example.

So it's not GOG's fault. In most cases it's just bad, or better yet old, software design from ages past. And in most cases there's really no way around it other than granting admin rights.

Previously it was. GOG has changed this behaviour recently due to the problems it caused with many games. It may be that admin is not needed anymore after that (as long as they are not installed to Program Files), not sure though.

Considering how MS keeps changing their OS idiotically, I wouldn't be surprised if In Windows 9 you couldn't install any games/apps unless they get installed to the default application directory (ie. program files). And Microsoft would justify that with security concerns and somesuch. Meaning, the current new GOG game installers would fail by default as they try to install outside of Program Files.

But who am I kidding? Probably in the future Windows versions you can't install games at all unless they were bought from MS App Store.

Because you don't give a shit about safety standards set by all other operating systems on the market doesn't mean that GOG should as well.

The problem still exists.

Also, renaming the executable removes the requirement for the admin priveleges. GOG.com, why? Just... why?

How is it possible that works?

I have no idea man, but it does. Just copy or rename the executable and the admin requirement is gone. Works on all Daedalic games and Rayman Origins, for instance. Will try with more games later.

As I recall, the flag isn't set on the executable, but it's a filename->compatibilities set in the registry. Modifying the executable means its hash changes, and programs may refuse to work, not to mention the fact that you can no longer verify if you do have the proper executable.
On the other hand, removing the executable and replacing it with another with the same name retains any compatibility settings there might have been.

I lost you there. My reply is about why renaming a file clears its compatibility flags.

So, let's take Reus for example.
Reus.exe is set up by the installer to be run elevated. That flag has to be set somewhere. If the flag is set on Reus.exe, that executable will be different from one without the flag, simply due to the extra flag. Reus.exe may not give a damn if it's modified or not, but if support asks you for the MD5 hash of Reus.exe along with its last modification date, that could lead to problems.
Thus the flags are set in the registry, not on the file itself. The hash of a file remains intact, and it's the same no matter the filename. The registry check though is simple a location\filename check, and it doesn't care about the rest of the file. If you copy cmd.exe to a file that has compatibility flags set, (again, for example Reus.exe), the cmd will be run with those flags.

P.S. There are some executables that have the elevated privileges requirement coded into them, such as the GOG installers and a few more. I'm not sure what triggers that requirement though, or when it was introduced.

Its a general umbrella to see that most things that would otherwise be stopped simply, aren't.

I have never had this problem. I always install outside the default directory.

The install path doesn't matter. You can have software in Program Files that runs without admin privileges.

UPD:
Figured this out. Funny enough, much easier than I expected:
Properties -> Compatibility -> Run as administrator

Why on earth would you force that flag by default on all the games, GOG.com? Seriously, why?