Well, in my vision the game is short excactly for those reasons - the first playthrough is a careless tutorial, and then when you take the pacifist route, things get intense and you thank the divines that there are only 10 levels. This is a game that is indifferent to your actions, but you may care about it's output, making your actions matter. That's why the same rules are always applied, to give the freedom to do anything the player wants. Maybe someone will try and not kill anyone from the start, that would be interesting, and it's exciting as a possibility.
Thanks a lot for trying it out!