Here's the way it works - there is no DRM; however, the only way to update the game (if you bought it at retail) is to update it through impulse/steam.  So, there's no real DRM - you are just forced to use a client to update the game.  Bottom line:  no DRM.

Yes - there is a CD Key.

I'm not 100% sure where you get the digital download from at this point if you purchase the collector's edition.  If you want to know, shoot an email to [email protected] and I'm sure they can answer any question of that sort for you.

I think there are actually 3 places you can get Demigod digitally at this point:  impulse, steam, or directly through Stardock's new online store. 

Thanks for the suggestion.  But I don't like Steam.  Aside from Steam as a DRM, I really don't need another piece of software running when I play my game.  And I really don't care for its update management.  So, I bought the game off this website.