That was one refreshing part about Arkham Asylum that the character I was controlling didn't have an arsenal of guns to shoot bad guys in heads. A bit difficult to get used to at the beginning since it was so different from how I usually stealth (kill all the guards so they can't find me to call for reinforcements), but that's a good thing.
It was a bit weird, however, to hear all the voices from the animated series in the game and see dead guards the Joker and his henchmen killed. Not that death doesn't occur in the Batman storylines, especially the most recent movie, but it almost never did in the 90's cartoon. It was some strange mash up of nostalgia and present day that was mentally jarring.
So, yes Rebecca, I too enjoyed not killing anyone. And the costumes were well done. Keep it up.