As for Demon Assassin and Oculus, fix is very easy actually (at least for offline gaming). Just go to registry (run -> regedit). Then find your demigod keys. Path is something like HKEY_LOCAL_MACHINE -> SOFTWARE -> WOW6432NODE (only if 64 bit operating system, otherwise skip it) -> Stardock ->ImpulseReactor -> Demigod -> DLC
Here to the right are numbers from 1 to 10. Few of them have a data written as a number "0" instead of "1". Change those "0" to "1" and it might fix demigods.
However, once you log on to your account in game. Registries might reset... So just a warning.