One is enough - I want to be able to play games on my operating system of choice (Linux). That's it - as simple as that.

And I'm not even commenting on your criticism of Linux above (too much wrong stuff to refute). Where have you been for the last 15 years? Linux is way better and flexible than it used to be.

It might be 'on par,' but the truth is that it's waaay easier to develop for DirectX than OpenGL, not to mention the entire thing of DirectX encompassing input, sound etc. while OpenGL only does graphics.

Truth be told, I was incorrect. I should have referred to Direct3D and not the whole DirectX suite. Alas, this all comes down to developer experience and preference but OpenGL (and the rest of the related media libraries) development is on par with DirectX. The fact that developers are better trained for DirectX shouldn't be a deterrent since we're taking in consideration non-windows development altogether (see: consoles, Macs, mobile devices, etc etc) and those don't support DirectX either so it doesn't matter.

All in all this isn't (or, rather shouldn't be) even what we're talking about here, the main topic is about supporting already existing Linux games, not porting Windows games to Linux.

I think what was meant is Direct3D (which is compared with OpenGL). They are on par quality wise. For sound there is OpenAL for example. Many also use SDL as an encompassing framework:

https://en.wikipedia.org/wiki/Simple_DirectMedia_Layer

It's pretty easy to use (easier than DirectX).
See https://www.youtube.com/watch?v=r3wDnOAjrtk

does linux come with Steam keys?

For one: SDL is awesome. But, and I have not said 'Direct3D' but 'DirectX' for a reason, it's objectively easier to develop DirectX applications than OpenGL + whatever applications, because of documentation and consistency troughout the entire suite. I'm not saying development for OpenGL+all the rest is oh so much more difficult (altho from my experience it is,) but that it's way easier and much more 'natural' to learn DirectX.

I think latest OpenGL is pretty consistent. It's more of a MS FUD to claim that DirectX is any better or easier to use.

I'm not talking about OpenGL per se, I'm talking about all the various frameworks you need to use to get DirectX functionality - while all parts of DX are consistent, all parts of development via 'whatever's avalilble' isn't

That's not a serious benefit if it comes with lock-in and Windows only result. Cross platform methodology can be more involved, but learning it pays off in a bigger way.

Well don't tell me, I've abandoned DX and am learning SDL :-P But most people are lazy and as long as there's a competition between two platforms that can be used to achieve the same result (aside from compatibility,) they'll go for the easier one.

Holy crap.. so many big words! I am having a hard time absorbing all this information..

Not to mention the Windows slice of the cake is likely "big enough" for them.

Because GOG doesn't want to simply put up a .tar.gz file that the users have to figure out how to extract/install themselves (or even .deb and .rpm packages), but a single shiny installer that works everywhere it's supposed to.

(My guess for what they'd like: the simpleness of a .deb/.rpm with the universality of source.tar.gz, coupled with some nice GOG.com branding throughout the installation process.)

But no, it's not GNU/Linux that need to be ready for GOG, it's GOG that needs to make a decision and work out how to support GNU/Linux and whether the gain is enough for the cost needed. For now it seems they've either decided that they do not have the capacity/capability to give GNU/Linux the level of support they'd like (even if that may be a higher level than most vocal people are asking for), or that the cost of doing so would be too high.

Perfect. I was going to make the same points but you've just said it all.