It is R for a reason, and the series itself has graphic and gory violence and strong sexual innuendos. It's generally advisable to never take kids R rated movies, excluding some rare exceptions like passion of the Christ. But if your kids play MA video games then this anime won't have anything new.
That being said I enjoyed this movie, it was the perfect length arc for a movie. All the characters are seamless from the show, and a great story for such an absurd universe.