Well, at least your game isn't a mess that is on purpose.
I played some time the 1.6.4 and don't remember you can sacrifice vampire or cursed ghost. I'm not sure I even tried but I'm sure Ghost and Cursed Ghost was a favorite since 1st game and I used sacrifice a little relatively soon. It's possible that in older version that was possible. Myself I never played an older version than 1.6.4. Is the steam version was older than that?
Is anybody here have been able to sacrifice vampire and ghost with an older version of the game I wonder? Other than that it's not so rare that people think of something and post it without to try it before. Well I probably did it too.
EDIT: It's also possible that some intermediate version got a bug allowing sacrifice Vampire/Ghost.
EDIT2: A point is that sacrifice English description doesn't mention it works only on living.
EDIT3: The fan guide of version 1.6.4 doesn't mention that restriction too. Lol. Eventually my 1.7 version has an ugly bug not allowing sacrifice undead! I have the 1.6.4 version or 1.6.5 and could install it to see but well...
