First of all, this is ABSOLUTELY unsupported by the developers of this game. If anything breaks, don't come crawling to Nightdive!

Now that you have been warned, make sure you have:
- A GPU that supports OpenGL 3.2. There is no way to get around that.
- You're using Windows Vista 64bit. There is no 32bit executable.
- Service Pack 2 has been installed.
- You have a spare machine with at least Windows 7 so you can install Steam and get the files of this game.

Alright, let's go!

Windows Vista lacks some system calls in its outdated kernel so on a bare system, the game will simply not run.

So what we need to do here is install an Extended Kernel for Vista that gives it some of the functionality from Windows 7.

If you've updated Vista to SP2, you're probably on version 6002. For the Extended Kernel to work, you actually need version 6003 though, which is an optional update that might not be installed on your system.

To check your version number, type "winver" into the start menu and check it.
If you're on 6003 already, everything is golden. If not, you can install the update KB4474419 for Windows Server 2008 (yes you've read that correctly) manually:

https://www.catalog.update.microsoft.com/search.aspx?q=kb4474419

Next, get the Extended kernel from here and install it via the setup.exe:
https://ximonite.com/win32/download.html

The game will probably still not launch, because it's hardlinked to a d3d11.dll. DirectX 11 is also an optional update for Windows Vista, so you probably won't have that either.

Install DirectX 11 via the update KB971512. Here you can use the version for Vista x64 directly:
https://www.catalog.update.microsoft.com/Search.aspx?q=971512

That's it, everything is ready for the game to work.

Steam will not work on Windows Vista, so what you'll need to do is download the game on a more modern computer.

Copy the folder
C:/Program Files (x86)/Steam/steamapps/common/Turok 2 - Seeds of Evil
to your Windows Vista machine, wherever you want it.

Now look for the Goldberg Steam Emulator on Google. This software is highly controversial, so I'm not linking it here.

Make sure you copy the steam_api64.dll of the emulator to the game directory on your Vista machine.

Next, create a steam_appid.txt file with the following content:
405830

Now, open up the kexengine.cfg and look for the entry:
seta r_rhirenderfamily "d3d11"
and change it to
seta r_rhirenderfamily "opengl"

If you now run the horus_x64.exe, the game should launch.
I know it's absolutely stupid to do this, but I had fun - I hope you do, too! :D