(update: and it's playable :) )

So, just putting this down somewhere:
-dx8 to dx9 converter to circumvent the artefact distortion on the popups when hovering the mouse over a unit (in non-standard resolutions):
http://enbdev.com/convertor_dx8_dx9_v0036.htm

-resolution options (at least for the gog.com version) can be set manually in the registry here:
HKEY_CURRENT_USER\SOFTWARE\Classes\VirtualStore\MACHINE\SOFTWARE\Wow6432Node\Black Cactus\Warrior Kings Battles\Renderer

-game pauses whenever a music track changes:
(edit: unregister l3codecp.acm, install alternative)

I've filed a support ticket on this, and will update once I or gog figures it out. It's a codec problem, and it is fixable, but I can't seem to remember what codec I disabled or what codec I updated to avoid it. If anyone can help, or remember what codec is used, please post.

edit: Best guess: an outdated mp3 decoder that was bundled with windows? Unregistering l3codecp.acm made the lock-up problem go away, in any case. If you install something like K-lite (standard package, 13mb http://www.codecguide.com/download_kl.htm ), the install routine will do this for you automatically. I'm assuming that this bundled version of the fraunhofer codec has some issues with third-party players, or specific function calls, but works brilliantly with WMP (and vice versa)... I do not think that this was a problem when the game launched, since a bundled codec that supercedes library overrides probably didn't exist.