Hi,
I do not test my scripts on Mac given that I'm only using Linux, and GOG rejected (or at least did not understand) our request to have a shared use license for the whole PlayOnLinux/PlayOnMac development team so that Tinou, that has Macs, can test GOG games also.
Still, I'm enabling PlayOnMac compatibility flag by default as per Tinou's advice (I assume, because it works "most of the time").
Have you tried enabling Wine's virtual desktop? (Right click on shortcut > Configure Wine > Graphics tab > Emulate virtual desktop). Start with 800x600, as Dungeon Keeper engine can have problems with high resolutions...