I don't know if this has been asked before-- I'm fairly new to GOG (having discovered it during the Christmas sales) and I'm loving everything about it-- but I'm wondering why we even need to install games in the first place. Especially with all the OS incompatibility issues with trying to tie into the system. The way I figure it, games don't really require any OS features -- there's no associated file types, for example. The only reason why you would need it is so that you can get an icon on the desktop or in the Start menu or something.
I'd really like to see GOGs unzip into a standalone folder you can place anywhere. Saves also go into that folder so you can just copy the game over to another computer. They're DRM free anyway so this would make reformatting your computer easier, just back it up and copy it back onto the system and you pick up on your saves right where you left off. Uninstalling is easy, just delete the folder. The game shouldn't need to copy additional files or drivers anywhere else.
Anyway, just a thought. Is this even possible?

I always hated the advent of registry with Windows 95. It was much simpler to deal with install/uninstall before.

Depends on the game.
Several games need registry entries to store all kind of information like resolution, paths, variables, etc... (games like the elder scrolls even write the controls into the registry).
You could store all this information into .ini files, but it's still the developers decision on how they do things.

For some of GOG's games (the DOSBox ones), it basically already does that. The installer just provides the shortcut and the uninstall entry. However, for others, they are still Windows executables and do require both registry entries and some OS access to function. GOG can't really change that.

A little bit off topic here but I for one like the registry: it's nice to have all that data in a central place and not scattered around hundreds of config files. Also, you can heavily tweak a lot of things fast if you know what you're doing instead of manually editing lots of files.

On the other hand you can screw up entire registry even with simples changes if done wrong and you are likely to do just that if you are not 100% sure what you're doing. Registry gets bloated over time as most programs and games do not remove all their registry entries.
Separate ini files are superior to having settings in registry in every situation. Using them is simpler, safer and reguires no ties to OS.

One of the problems with tying things to the registry or the OS is the compatibility issue. Windows Vista and 7 have built in required amounts of bloat simply to deal with old programs. What if at some point MS wants to get away from using registries entirely? What if they want to change the format?
DOSBox is a great model, it does exactly what I mean about keeping things self-contained and you can just delete the folder when you're done. Maybe what we really need is some kind of WinXPBox that simulates a bare-bones XP Virtual Machine to install and run a game in.

1. It is highly unlikely that MS is going to remove the registry
2. If they ever did, there would be more problems than just not being able to run your favorite installer
3. DOSBox is not a "model". It is just the nature of the platform it is emulating. DOS didn't have a registry, so DOSBox doesn't need to handle one. Simple as that.
And if you wan to make a barebones WinXP Virtual machine:
MS has Virtual PC
Sun has Virtualbox
Both of those will work, albeit with differing levels of performance. I used to play Chaos Gate with that, until Win7 (which can handle it).

I recall them saying they were trying to do just that before the release of Vista or 7 (I forget when it was). Didn't happen though.

From what I know they never said such a thing. Removing the registry would break almost all backwards compatibility in one movement and that isn't a thing Microsoft wants to do.

Bingo. Half the "problems" with Vista and Win7 are because they need to maintain backward compatibility.
Everyone thought it was a ripoff that DX10 could (effectively) run in XP with just a simple dll. And, to be fair, I doubt there was all that much that required the kernel changes in Vista/7. But it was also because MS had to maintain backward compatibility. If they put too many nice things that actually DID need the kernel tweaks, they just broke compatibility with XP.

Well the registry is pretty much made to provide a central repository for important OS information. That way whenever something tries to run DirectX routines, use codecs etc, it only has to search one database to find the location of the dll rather than search the entire hard drive or have the locations hardcoded. Give me the registry any day.
People who break it from tinkering learn 1 of 2 things, either what they did wrong and not make the mistake again or that they have no business going anywhere near it and have no right to bitch about their computer being broken. Seriously its morons like that who are responsible for that nagging user account control

The good part is that we're seeing movement on that front with the implementation of XP mode which can mean that in the future MS will make the same move Apple made when it adopted Rosetta for backward compatibility (providing a seamless VM environment in which apps can run).
Sure, it's not the same as Rosetta (yet) but it's a step forward.

Yep. I find it funny how people think of themselves smarter than the engineers who built the registry and try and edit it without knowledge. They're the same people who manually manage the page file thinking they're smarter than a finely and carefully tuned piece of software built by a team of experienced engineers.

Well. As Linux (and Mac OS, in extension) proves: An Operating System does not need a registry. I am fairly certain if Microsoft could they'd drop that thing.
Problem is increased because programs really do tend to overuse the registry. As said above .ini's / .conf's are nearly always the better solution. The average normal user will (hopefully/usually) never touch the registry or .ini/conf.. The more advanced ones should really know where there programs are installed and hence find those .ini / .conf if they really want to play with them.
I.e. I don't see the argument that a central registry is in any way useful, especially because everything adds to it. If you do not know what you are searching for precisely, it can quickly turn into that haystack / needle thing.