Thanks to the mythology and the non-player characters tailored to it, the result is quite interesting and, most importantly, logical. You can't achieve that with a standard setting.
P.S. I've already spotted a couple of roles that I wouldn't mind playing.

P.P.S. Veg, is it okay that in that Mafia game, the roles were chosen first, and then the non-player characters were revealed? I guess I haven't fully grasped it yet; it will become clearer as the game progresses.