Some agreement on where to store save games would be appreciated as well.

I thought that's appdata. It's not Microsoft's fault that programmers choose to save stuff whereever, they could enforce it a bit more tho.

Well that's great news. So far, with EVERY SINGLE game i've installed from GOG, i've had to change the default location AWAY from Program Files. i grew frustrated with this after the first dozen. Would be nice if the installers simply remembered where i put the last ones. Really it's no big deal though. My biggest beef is getting update messages but having absolutely no information on what would be updated. That's actually begun to piss me off.

I always thought "My documents" was the latest dump site.

A lot more. Games For Windows (not Live) was a good scheme but it was too little and too late. They should have had something like that at least by the time that XP was released, if not before.

Most saves go there. But not all. I lost all my Napoleon Total War progress because Creative Assembly insisted putting the saves in the most obscure location they could think of. They're not alone in that either.

Stuff that you isn't made for you to access and is made for access from the program should go to appdata, data that you should be able to access with ease should go to my documents. Programs should go to program files.
Most programs put their shit right now even on windows. There are a few exceptions (why does xchat put chatlogs in appdata?) and it is partly MS fault because they quite often ignore their standards and in some cases I'm glad that standards are ignored like the "programs that are active should always be visible in the taskbar".

The first time I encountered this issue was with the installer for Treasure Adventure Game, released in 2011. Meanwhile, the much older Imperialism does not have this restriction (both with 2.0 GOG installers). It seems entirely arbitrary whether installers have this restriction or not.

This just seems like a weird, stupid bug to me, more than an intentional restriction. At least I hope so, because if it was done intentionally it's even more idiotic. (Perhaps the programmer forgot that parentheses are allowed in Windows pathnames?)

But my main point was that I really wish they would just use a standard installer. This is by far my biggest complaint about GOG.
Wouldn't Saved Games be a logical place?

In that case they have added the requirement to all then. Well... Interesting choice, especially for new titles - at any rate, there are suddenly no more complaints about bugs caused by installing to default 'program files' or about game saves / whatever not working because of path with 'special' characters, and complaints about GOG restricting special characters are few and far between, so I'd say it was a good call on GOG's part. Sort of. I'd agree that a warning would be a prefferable solution, but ... Well, people are idiots, they won't read no warnings!

What is a standard installer? GOG is using innosetup, what's non-standard about that?

You'd think. But I've never known anything use that.

Hahahahaha.

Don't get me started on installers for Windows. If you want to clear a room full of developers FAST just utter the words "we need someone to work on the installer" - you wont see them for dust.

And that's when you are developing your own software with full access to the source to fix any incorrect assumptions/mistakes about file/resource placement.

I shudder to think what GOG have to go through to successfully install games that have been developed from before Windows existed all the way up to current games via every version of Windows with little or no access to the source.

A few things do. Looking in it shows AGS games and ScummVM here.

There's probably many more but I just reinstalled hence the small number.

Soooo, people still install their games into "program files"?