Under all the sci-fi names and gizmos and ideas, DUNE is essentially just a war movie. The hero, Paul, is apparently "the chosen one," and thus he never really has to make a choice; his destiny is laid out for him. When he finds his place, the first thing he does is declare war on his enemy. The objective is to free the desert planet Arrakis, but it's arguable whether or not the end justifies the means.
The movie is filled with fantasy-style battles as well as some burning flesh, spurting blood, gore, and torture. We see knife fights (with stabbing), poison gas, kicking, biting, and punching, a severed head, scary monsters, and scary noises, and a special kind of voice-operated laser gun. We also see a scary floating killer hypodermic needle (a "hunter-seeker"). There is a scene in which a rat and a cat are strapped into painful-looking positions and locked in a cage. Notably, there is a young girl character (played by Alicia Witt) who wields a knife.
Paul and Chani are seen in bed together, with naked shoulders, but nothing else. Sting appears nearly naked, wearing only a tiny speedo, and Lady Jessica wears a sexy nightgown in some scenes. Characters flirt with her and tell her how desirable she is.
"Goddamn" and "oh my God" as an exclamation.
Everyone in the film is after "Spice," a powerful substance that allows users to travel through vast amounts of space and to live longer. There are also side effects, such as glowing blue eyes. The "Spice" is never demonstrated as being dangerous, but the behavior of the characters around it is a bit like drug dealers on earth. There are also some "drug trip"-like sequences.