R rating for killing joke seems a no brainer.
It's been a long time since I've read the comic but wtf is this about Barbara Gordon being sexually assaulted?
I vaguely remember both her and gordon being stripped naked at some points, but don't recall anything more then that.
Otherwise boo to this "dc films getting too dark" suggestion, no, I was actually quite pleasantly surprised by the violence of some of the more recent DC animated film and appreciated it because violence is messy and horrible, it shouldn't be portrayed as having no consequences or things you can just shake off after being unconscious for 5 mins.
I feel sanitizing violence is actually counter productive for all sorts of reasons and DC films are hardly aimed at a young kid demographic anyway so no reason we should be coddled.