Happend on Kubuntu 15.04 64bit, had absolutely no sound in any GOG games. Their deb packages do not bother to list dependencies, so you have to look for them manually using ldd and such, and even that is not sufficient.

Nevermind, after installing

libasound2-plugins:i386
libspeexdsp1:i386
alsa-oss:i386

sound suddenly started working in all GOG games.

Don't know if you need all the mentioned packages, just retracing my last few steps, hope it helps other people. Was frustrating enough.

GOG linux support leaves a lot to be desired.

I thought they listed those dependencies on the game cards (under system requirements)?

That settles it then. (though it might be nice if the dependencies were listed in the deb package too)

With that being said, I think it's generally a good idea to look at system requirements before purchasing a game anyway..

Actually I think the 'libasound2-plugins' should be enough for most (if not all) games sold here.

I'm a little bit surprised they don't.

Then again, I also kind of wish there were a way of setting up individualized PPAs for folks so they could just use the normal package management system to keep their games up to date.

I assume that's a lot of work on the back end though.

I think the hard part would be the authentication system, especially if you think that each user should have access to only a subset of the games present in the repository. (EDIT: unless you set up one repository per game of course)
By the way, if you have some information on setting up an authentication system on an APT repository, I’d love to read about this ;) (I’ve some projects that would require this kind of system)

I don't particularly. I know that doing it with FreeBSD ports and packages would be trivial, so I would assume that doing it with a ppa wouldn't be much more work. But, I haven't ever tried to make my own PPA, so I'm not so sure.

With ports, you'd probably just make the user enter a password or manually download the package and the port system would pull in all the dependencies.

As I know, apt-get doesn't have support for any kind of authentication, so PPA is probably very unlikely. That can work for freeware and free and open source software. But for commercial software, no. At least I haven't heard it ever did. :)

But, having PPA for the Galaxy Client (in a close future)... That does make sense.

I think Ubuntu uses some kind of app store (for paid software), is it not based on APT?
If so, it must perform a check at some time to let you download only something you bought.

I’m going to do some research on this.

Good point. I don't know really. :) But I would be interested to know more if you find out anything.

Edit:
Although I highly suspect they are using in-house developed solution integrated with the application center.

Edit 2:
Thinking again: knowing Debian, it's highly unlikely it's integrated with APT. So most probably an in-house addon.

It's common practice that packages that have dependencies obtainable from the general repositories (like the mentioned libraries) install said dependencies before installing themselves.

Installing a package without dependencies, saying it's "complete" and then failing to run is simply not good enough.

Another option would be to have a package that doesn't actually install anything, but depends on the packages that do need to be installed. Debian commonly does that for transitional packages, like when the name of a package changes, the old package becomes a dummy package that depends on the new one.

The packages built by my "./play.it" project come with dependencies management. Maybe you’d like to give it a try?

-----

I think I found something about APT repositories with restricted access:
https://www.debian-administration.org/article/513/Restrict_Access_To_Your_Private_Debian_Repository

Those look more like workarounds. :) It doesn't have anything to do with apt. it's more about putting the restrictions to the service hosting the files.

But, you are right. That's the way too. Just not that direct and kinda too much of a work around to be useful for a commercial use (I think). :)