Just as a heads up to those of you on Vista/Win7 (Usually 64-Bit but there have been issues elsewhere..) I-War 2 can suffer from Graphical tearing and glitches that make the game nigh-unplayable on modern systems.
Unfortunately, it seems as though a fix was not found for the GoG release,. (Although the support tip of disabling SLI/Crossfire may help you, you're out of luck if you're running only one GFX card.)
You can find out more information about the problem here: http://www.ataricommunity.com/forums/showthread.php?t=689801
I was hoping it would be fixed, but as it's not, a few people may end up with a $6 bookend on their game shelf. Feel free to update this if a working fix is found, as I know I'll add whatever information I can find as it comes.
Current Possible Fixes:
Turn down Shader Settings in the graphical options. Some have had luck on anything lower than 'High', some have to go as low as 'Low.' Combine this with disabling 'Starfield Quality' may fix your problem.
Turn off Hardware T&L Lighting.
Both of the above buy me about 5 minutes of playtime before the glitches return, your milage may vary.
Some have reported turning off V-sync as well as Multi-textures on top of doing the above, while others suggest playing at a lower resolution helps.
Others still are perfectly fine on similar systems to those having troubles.

Sorry, but I don't have the knowledge or expertise to fix it. You'd need a programmer for that, and you'd also need the source code which only the rights holders can authorise to release.
I still have the unreleased DirectX 8 patch, but it doesn't really work anymore unfortunately, at least the planetary ring shadows don't work. The bump mapped planets and asteroids do, but they don't really add much to the game. If it fixed the rendering issues it'd be worth GOG using it, but it doesn't. :-(

I wonder what stage GOG is on. Trying to pull some strings in the nVidia Control Panel didn't help...

On my disc version fiddling with the Shader settings and setting the loader.exe's affinity to 1 core worked.
It's a shame we can't have the shader settings at max, as you lose all the specular and shiny effects off the ships.

Hey :)
This did fix the issue to start with however it starts happening again once I get to the menu in Lucrecia's Base. I have the retail version so this may be something that doesn't affect the GoG version.
Karl

Attempted to run with Loader.exe on one core, and lowest settings resulted in an instant crash as soon as the game environment was loaded.
Despite trying to force this to work, the fact that we hear a guy that worked on the game tell us it's a DirectX dll issue tells me there's not much we can do here.

When I was playing with the settings the game didn't seem to like 640x480, so if you're trying the lowest settings it might be a good idea to avoid that resolution.

At the moment, I'm just playing at 1650 x 1080 at16 bit colour depth and have no problems with everything else set to max. At 32 bit colour depth I get the glitches as described.
16 bit doesn't look quite as nice as 32 bit, but it's not a huge difference.

Which OS and GPU are you using?

I'm similar. Win 7 64bit though I have only one card - 8800gt. I'll try the latest beta drivers though :)
Karl
Okay. I'm using the nvidia drive 258.96 and things seem to be okay with Shader at the lowest setting and 16bit resolution. Will be playing with it some more soon.
Okay, lets see.
Shader = low
Resolution was change from 32 - 16 and then played. I crashed (as well as graphical glitches) at L-Point Alexander.
I'll try again soon with 16 bit resolution but at the moment I'm tired of repeating it :p
Karl
It seems to be running fine except occassionally glitching when coming out of LDS. As long as don' move until the glitching stops it appears to be good.

Apparently my "seems to be running fine" breaks just as I exit LDS at the Aldo Mine. I haven't managed to get that to work again.
Karl

On the off chance that I had a damaged download, I uninstalled and reinstalled, go the newest drivers. At this point, I'm very frustrated. The game just won't run beyond the main menu.

These tips helped me resolve my issues! Thanks a ton guys!
i7 975, GTX 295, 15GB RAM, Win 7 Ult 64bit

@ Alkpaz2
If you could tell me what you did, I'd greatly appreciated it.
Q9300, GTX 260, 3GB, Win7 Ult 64bit
Much appreciated.
Also: any word from GOG.com on the matter?

Hello Ravenger,
I'm still dreaming of this dx8 patch... Even if you already said, on other forums, that you can't share this patch for legal reasons, can you show us some exemple pics of the bump map effect?
I'm sure it will help me (or us) to stop fantasizing...