First: I haven't downloaded or installed the game.

My question is: What's the deal with the missing multiplayer? Were they simply not able to make it work in Windows 7? According to posts on the internet, multiplayer seems to work using Dosbox. So why didn't they use that?

I'm simply curious what exactly the sentence on the (game page ) means:
"Due to technical issues beyond our control the multiplayer mode is unavailable."

KKnD uses an old IPX protocol for its multiplayer. WIndows Vista/7 don't have that protocol supported. I've tried installing it on a XP virtual machine (not a real VM, but the one for Windows 7), but said invalid configuration. Trying to launch the game itself without the wrapper results in "DirectDraw not found error".

So it looks like they wrapped up KKnD in something that allows it to run with fake DirectDraw.

KKND multiplayer works fine in DOSBox with IPX emulation enabled, yes. They didn't include the original KKND because they didn't have the time to test it properly, must likely, to bundle it with the Extreme version. You should be able to buy it on Amazon, though, if you really want multiplayer. :)

But let's hope somebody fixes the Extreme for version for Windows! Then we'll be able to play in high res, too, in multiplayer.

Multiplayer works fine (I use Win 8 x64).

You must enable Windows XP SP3 compatibility mode on file KKNDgame.exe (this is original exe file from game). And then run directplay-win32 or directplay-win64 (it depends what architecture of windows you use for). At the end you run the game from original KKNDgame.exe (NOT from GOGLuncher.exe).

That's it :) Multiplayer and game work's well.

P.S. GOG put in game IPX wrapper that works only in LAN over TCP/IP (for example hamachi) and you must know IP of client/server to play multiplayer. More info here: http://www.solemnwarning.net/ipxwrapper/

Define 'works well'? Because I tried it and the multiplayer definitely has desync issues when running Windows 7 64. The first few seconds the game does does run fine, but then the game starts to slow down and the gameplayt gets rather laggy. I should say that only one of my machines would run with XP3. The other needed 98 to not crash. Maybe that's the issue. However, I actually doubt anybody is able to run the multiplayer without performace issues. Maybe you're just one of those that cannot actually tell that there's a performance issue? Kinda like people that cannot tell the difference between 20 FPS and 120 FPS, you know. No offence ment, of course.

Anybody have any experience with using XP machines?

Indeed (to open source it). Besides, KKND Xtreme is by far the best KKND. KKND 2 is kinda bad, imo.

You can actually already hex edit the exe to get higher resolutions, though. Like 1920x1080.

**Update

Okay, so the lag issues I was talking about was an issue connected to using 98 mode. I found out why the game was crashing using XP3 on my second PC. I then did a rerun and the lag is mostly gone now. Ye! So Wildchild was indeed correct that you can get MP to work quite fine in Win7. However, I did notice a few seconds of slowdown every 2-3 mins. Nothing too bad. Maybe WinXP do don't have that small issue or maybe it can be fixed. I'll using affinity (single processor). I'll post more when I have tested it further. Now it's time to get 1920x1080 resolution working!

Edit:

XP2 and Win7 mode works, too.

I am having crashes only when trying to play this game in multiplayer on IPX about 30 seconds when in the multiplayer game. I tryed Win98 and XP2 and XP3 compatibility mode, ran the directplay-win64 and tryed with kkndgame.exe and goglauncher. I am curious to find out how you figured out why the game crashed. thanks

Did anybody managed to run multiplayer on Win 10?
The game krushes as soon as I click Multiplayer in main menu :/
Tried to run it from KKNDgame.exe in WinxP SP3 compatibility with no luck..

Multiplayer for kknd1 is lan only. KKnD2 works somewhat unstable online too if you are lucky.

both games have functional multiplayer at the moment. i played both multiplayer myself actually but, only on lan.