Seems that one of the cardinal rules of DC superheroes in the comics won't be kept for the cinematic universe interpretation.
"Man of Steel" SPOILERS AHEAD
In the case of "Man of Steel," the ending has caused much debate amongst fanboys over the scene in which Henry Cavill's Superman kills Michael Shannon's General Zod. Delivering a lecture recently for BAFTA and the BFI, the film's screenwriter David S. Goyer spoke at length about the decision to include that scene:
"We were pretty sure that was going to be controversial. It's not like we were deluding ourselves, and we weren't just doing it to be cool. We felt, in the case of Zod, we wanted to put the character in an impossible situation and make an impossible choice.
This is one area, and I've written comic books as well and this is where I disagree with some of my fellow comic book writers - 'Superman doesn't kill'. It's a rule that exists outside of the narrative and I just don't believe in rules like that. I believe when you're writing film or television, you can't rely on a crutch or rule that exists outside of the narrative of the film.
So the situation was, Zod says 'I'm not going to stop until you kill me or I kill you.' The reality is no prison on the planet could hold him and in our film Superman can't fly to the moon, and we didn't want to come up with that crutch.
Also our movie was in a way Superman Begins, he's not really Superman until the end of the film. We wanted him to have had that experience of having taken a life and carry that through onto the next films. Because he's Superman and because people idolize him he will have to hold himself to a higher standard."
Goyer was also asked if he was writing the "Justice League" movie, to which he responded" "Might be, can't say."