Dystopian depictions are always imaginary. Although Hitler's Third Reich and Stalin's Soviet Union certainly qualify as horror societies, they are still no dystopias. The very purpose of a dystopia is to discuss, not depict contemporary society or at least contemporary mankind in general. Stories like Taxi Driver and Enemy of the State may have dystopian qualities, but they still depict reality, however twisted the prerequisites of those stories might be. Dystopian depictions may borrow features from reality, but the purpose is to debate, critisise or explore possibilities and probabilities.
Dystopia is not really about tomorrow, but rather about today or sometimes yesterday. Nevertheless, dystopian stories take place in the future in most cases. The year 1984 may have past, but George Orwell's horror story described a plausible future scenario when it was published for the first time in 1949 and it may still come true in a not too distant future. Interesting exceptions from this rule are uchronias, so called What-if? stories, like Fatherland.
Dystopias have always been a powerful rethorical tool. They have been used and abused by politicians, thus making dystopian stories controversial. The anti-totalitarianism in Nineteen Eighty-Four is explicit, but the anti-Reaganism in Neuromancer is implicit. The war-ridden world in the Mad Max triology is obviously a Dystopia, but it would be ridiculous to call it a political statement, although one can claim it is a warning regarding the dangers of anarchy and Social-Darwinism.
The leitmotif of dystopias has always been oppression and rebellion. In Nineteen Eighty-Four, the pseudo-communistic party Ingsoc's oppression of the people is obvious, but the multi-national mega-corprotions' oppression of the people in Neuromancer is more subtle. The oppressors are usually more or less faceless, as in THX-1138, but may sometimes be personified, as in Blade Runner.
The oppressors are almost always much more powerful than the rebels. Consequently, dystopian tales often become studies in survival. In Neuromancer it is simply a question of staying alive, in Brave New World it is a question of staying human. In Nineteen Eighty-Four it is even a matter of remaining an individual with own thoughts. The hero, because it is usally not a heroine, often faces utter defeat or sometimes Pyrrhic victory, a significant feature of dystopian tales.
As the citizens of dystopian societies often live in fear, they become paranoid and egoistical, almost like hunted animals. Dystopian citizens experience a profound feeling of being monitored, shadowed, chased, betrayed or manipulated. The factors which trigger this paranoia may be very evident and explicit like in Brazil or more diffuse and implicit like in Blade Runner. The most extreme example of paranoia is probably the Thought Police and the thoughtcrime concept in Nineteen Eighty-four. As a result of this fearful atmosphere, dystopian heroes are not seldom monsters in many respects.
The dehumanisation of society may also be connected to the benefits and hazards of technological progress. Cyberspace cowboys refer to their bodies as "meat" and blade runners hunt artificial, but completely sentient beings like animals. In Dystopia, the borderline of humanity is often blurred and the very concept of humanity distorted.
Finally, dystopian stories tend to explore the concept of reality. Rick Deckard in Blade Runner is not sure if he is a human being or a bio-mechanical replica. Case in Neuromancer sometimes cannot distinguish cyberspace from reality. Winston Smith in Nineteen Eighty-Four is forced to learn that two plus two make five. In many dystopian tales the people in general and the heroes in particular get manipulated beyond reality.
Dystopian stories frequently take place in landscapes which diminish people, like large cities with mastodontic architecture or vast wastelands devastated by war and pollution. Dystopian societies are usually, but far from always, battered and worn-out. They may be colorless like Nineteen Eighty-Four or kaleidoscopic like Blade Runner, but always visually obtrusive.
For uncertain reasons, dystopian movies often use film noir features like dim rooms, rain wet asphalt, disturbing contrasts, symbolic shadows etc. Unproportionaly much of the action takes place during night in many dystopian stories. Possibly, this reflects the thematic relationship between dystopian fiction and film noir.
speaking, the environment plays an active role in dystopian depictions.
The environment is not only a fancy background, but emphasises the
message. A prominent example is Blade Runner: there can be no
doubt in the viewer that USA has become completely commercialised and
that the world is in a state of terminal decay.