So far from what I've played which is the current version it seems to be a remake with new content and some new bells and whistles. For example there's a new prologue so to speak. And you can change your characters name and player name so if you don't want to be called ainz ooal gown or momonga you can change it. That's just two changes. There are others as well, but I don't think I'll be able to do them justice. So I won't try to describe the other changes.