i think there are just a lot of games where a system-wide installation for multiple users does not work.
It's not about multi-user installation, but about privilege separation. And so far this has to work for all games were a .deb package has been provided. You just have to set the permissions on selected files or directories correctly in the package. This was not perfect, but a lot better than the new method which probably sets anything to be writable by the user which also executes the game. This widely opens the door for all kinds of malicious attacks.
hmm, i don't really see any dangerous attack vector. at least not on a standard desktop pc that is basically used by a single user. What exactly can happen when the user can overwrite the game files? The game executable doesn't do anything critically, so I don't see how it could lead to an privilege escalation. All you can do is execute some code with the rights of the user. But then, you already could do that at the point when you modified the game, right?
If an attacker can place some malicious code under your user account, your account is already compromised anyway. Having write access to a game won't make that any worse.
Unless I am missing something here?
Especially all those old DOS games who just dump their savegames and settings into the installation folder. But even some of the newer linux games work like this.
DOS did not know any better (and therefore got it's pile of worms and viruses). But newer Linux games, that's a shame. Any examples for that?
Kerbal Space Programm
i personally think treating games as personal data and throwing them into $HOME works just fine.
There's another reason why I don't like that, backups. Game installations can be quit big, so they either blow up your backup unnecessarily or you have to exclude the directories manually from the backup, which is tedious and error prone. That's also the reason why I want saved games to be separated from the game installation as there's no need to back up your game installation, but of course I want to back up my saved games.
I absolutely agree that this is a nice feature. I just don't think that we can expect that gog will develop such a solution for games where this doesn't work out-of-the-box. In the end they are just the distributor, not the game developer. Demanding a guarantee that things like that will always work in their installer seems unfair to me.
That surprises me seeing as that's what they use with those Live CDs, it seems odd to me that it wouldn't be in the kernel.
live cds usually have a custom kernel. But when making an installer that you want to work in as many environments as possible it's just not a good idea to rely on a feature that is not a standard kernel component.
Anyways, Linux is a multiuser and multitasking OS, it seems crazy to me that the games here haven't been set up to handle that.
well, as I said above. That is mostly up to the developer, isn't it? Not GOG. Depending on how the game exactly handles this, support may be easily added .. or it might just be so much work that it isn't really worth the time.
(ps.: i don't think there are any games that can't handle the multitasking :p)