But I did enjoy the levels where you couldn't blackjack or kill anyone. ...at least on Expert difficutly.
That would be all of the levels on expert difficulty, if I remember correctly. And expert is the only way to play.

But now that you mention it, I hope they provide ways to customize the difficulty level. I enjoyed the no killing requirement, but I grew to hate the high treasure requirements... running through a house a billion times trying to find the hidden lever for the last piece of treasure, even though everyone's knocked out so there's no difficulty, just frustration.
Ibe pretty cool to have some requirements for like no blackjacking allowed or a time limit before people start to wake up. All customizable, for maximum gaming pleasure, of course.