HARD question.
I've only played the first two expansions of the first game (there was ridiciuslly many expansions to the first game...), and I don't really know, to be honest. Maybe the key difference is that you don't really controll your charactre(s). You tell them what to do, but you can't talk with them, and if you don't tell them what to do, they will start doing stuff themselves. So it's not really you who plays the role as your character, you just gives him/her orders.
Übereil
