The movie centers on two strong themes. The first is about standing up to bullies. Several characters make good arguments why they shouldn't, but the end result is that not standing up to them gives them more power and allows them to win. The other theme is free will. Villain Owlman believes that since every choice made results in an alternate reality, nothing matters -- but the heroes don't agree with him.
Lots of fighting, ranging from old-fashioned punching to arrows, laserblasts, bullets, and assorted other fantasy weapons. There are also threats ("I'm going to kill you," "I'm going to beat you to death," etc.), characters screaming in pain, and some blood. Some minor characters die.
Lex Luthor appears naked (no sensitive body parts shown). Superwoman kisses two men and flirts heavily with them, with the promise of some rough "playing." J'onn J'onzz, the Martian Manhunter, kisses a human woman.
Two uses of "ass," two "crap"s, and one "what the hell?"