So I had to return Deadlock 2 because it does not work under Windows 8.1. So I was wondering, now that I have Windows 10 - will Deadlock 2 work? I would assume not, but if somebody has some firsthand experience...

Unfortunately it has issues with Windows 10 and 64 bit systems in general. Hopefully they'll fix it eventually.

I'm running Windows 10 and installed Deadlock 2, and can't use it. The introduction videos play normally, and the main screen shows up. But as soon as I move the mouse, the entire screen goes black. Only a small block around the cursor gets redrawn briefly, then goes black. The top of the screen displays "New Player", but nothing else is visible. If I click to another screen (by guessing the location of the menu), same thing applies. I can even start the game, but again moving the mouse turns the screen black. Looks like some kind of refresh problem that makes the game unplayable in Windows 10 for me. I'm running Windows 10 64-bit Home Edition with latest updates.

Running in compatibility mode doesn't work either. Selecting Windows 95 or 98 gives an error on startup. Selecting Windows XP or 7 gives the same screen problem. Adjusting compatibility settings doesn't seem to help.

(EDIT) Another user posted about adding "-w" to the shortcut, after the DEADLOCK.EXE target. That gets me a small window in the upper left. The screen displays normally, but the mouse overwrites whatever is near it with a pink square. The screen isn't redrawn, so anyplace the mouse moves is not usable afterwards. Seems like a wash for me - the game is not playable in either condition.

Check out the solution mentioned in thread "Deadlock 2: possible solution for black screen issue".

It resolved my graphics problems on Windows 10 64-bit. I've asked for the solution to be passed along to gog.com programmers, but have no way to track if that happened. In the meantime, a copy of "ddraw.dll" mentioned in the other thread might be your best bet.

I got it to work in Windows 10 (64-bit) by doing two things:
Placed the ddraw file in the game folder (mentioned above and in another post)
Changed compatibility to WIndows 7

No more black boxes or weird color schemes. Runs fine so far.

I did the black screen fix, it worked great. Now they game is determined to never let me finish a match. My game will either end in the AI planning its next turn for infinity or I get a double windows white error box, closing the game. They really need to update the exe personally. for the newer OS.

Does anyone currently have Deadlock 2 working on Windows 10?

Ok, tried what @moderately_neeto proposed (which is: download ddraw and put the file in the main folder + compatibilty mode on win7) and I can confirm that everything works fine, no more black screen or pink trails.
Use the link provided by W.A.S.T.E. to get the file.
Cheers guys.