I am a BIG fan of sic-if action thrillers, and this movie is by FAR the best sci if move EVER. The plot is genius, and the effects are amazing. Two things to worry about? The violence and gore, and the language. The movie says the f word every two seconds, and there are discussions about sexual retaliations between humans and aliens, and people making jokes like "did you wear a condom?" There is A LOT of violence, including firefights, aliens tearing limbs off, and weapons that explode full human beings. Almost all scenes have scenes with significant amounts of blood, which include experiments, surgeries, wounds, missing limbs, and guns that cause people too explode with blood, and skin. Overall, great movie, good for mature twelve year olds who can handle blood and ogre, and many dead things.