The game says I need a Deadlock-CD...
Is there a fix for this bug?

I don't speak German, but know Deadlock well enough to play in another language. I installed both Deadlock and Deadlock 2. I see a warning, but it's from Windows 7 : "Do you want to allow the following program from an unknown publisher to make changes to this computer?" I click "yes" and it starts normally. I can take a turn, save the game, and I do not get asked about a CD.

Did you purchase Deadlock / Deadlock 2 from here on gog.com? The gog.com version is DRM free, which means no CD check. But if you have your own copy, that may prompt for the CD.

I can confirm that it still asks for a cd, with both the Steam and GoG versions. DRM free doesn't mean that they didn't screw up somewhere with the port.

Yeah, it asks me for a CD as well. I think I might need to end up getting a refund as nothing I do seems to make the game play.

Did you run the game as admin?

Yeah. That led to the black screen whenever I moved my mouse (apparently, a common issue).

I solved both issues by running the game in a virtual machine using a stripped-down version of Windows 7's XP Mode. I followed Chris Hoffman's instructions in the MakeUseOf blog.

I can now run Deadlock 2 in Windows 8 :D