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No nudity is shown. But there's a part where Bruce and Kitka kiss, and two couples kissing on a boat, but they don't have sex.
There are numerous fistfights, and, in the exact same manner of the TV show that this movie is a spinoff of, the actual point of contact is covered by a large animated "POW" or "ZAP" or "OOOF". There is no blood shown in the film. In one scene, Batman is humorously carrying a large bomb across a dock area, trying to dispose of it in a manner that will harm nobody -- even to the point of stopping from throwing it int he river when a duck and her ducklings swim by.
No profanity in this movie.
The Penguin smokes through out this movie.
Maybe some kids might get frightened or disturbed by the Joker's laughter and appearance.