If nothing else, Duncan Jones’ Moon is a film you’ll have to talk about afterward.

Sam Bell (Sam Rockwell) is the sole employee at a lunar mining facility, just a few weeks shy of finishing his three-year stint. He’s playing to familiar territory… bearded and slightly unhinged. His only company for the past three years has been GERTY, a super-intelligent computer, voiced by an eerily calm Kevin Spacey. Sam heads out in the rover one day to investigate a problem with one of the mining machines, and discovers he has company… Another man in a company-issue spacesuit. A man that looks and sounds exactly like him.

This “big spoiler” for the film is revealed in the first 15 minutes, but even as you’re patting yourself on the back and mouthing “CLOOOOOOOOONE” to anyone you came with (if you’re as obnoxious as me, at least), Moon just steps right on and continues to explore fresh and insightful territory. This film has two persistent strengths. The first is that it does a lot with very little. It flawlessly renders the surface of the moon and the base, despite an extremely modest budget. Clint Mansell’s (Requiem for a Dream, The Wrestler) haunting and beautiful score spends a great deal of time on solo piano, a style that compliments the story masterfully.

But the second strength is simply the film’s respect for its audience. So much of modern sci-fi is merely elaborate, CG-infused setup with no payoff. Behold! A world in which robots are everywhere! And spaceships! And aliens! Now, let’s throw em all together and watch them beat the shit out of Will Smith or Shia LaBoeuf (or both)! Annnd…roll credits!

This film does what few sci-fi films have managed in recent years. It sets up its world, but then respects its audience enough to subtly raise the myriad of profound ethical and existential questions that naturally follow. The clone “twist” happens early, and the rest of the film is spent exploring the idea. How would you feel, as either the clone or clonee? How would the two of you interact? And oh, as long as you’re here, what does it mean to be human?

It is this last question that pervades the ending of this film, and in that grain, it owes a great deal to such works as Blade Runner or the re-imagined Battlestar Galactica. And all the while, as we explore Sam’s relationship with GERTY, we see the trappings of 2001 as we wonder when the computer will go all HAL-homicidal. But that is the triumph of this film’s storytelling. It is aware of the works that have come before, and pays them the requisite service while simultaneously passing a dozen points when it could easily veer into an obvious and overwrought cliche. It plays with the audience’s expectations, but delivers some remarkable originality.

Sam Rockwell’s performance may be the finest I’ve seen this year, imbuing each of the Sam Bells with a distinct, but related personality. One of them is strong, but struggles to make sense of what he is, as the other becomes increasingly erratic. Kevin Spacey gives a fine voice performance, although I suspect the intrigue of GERTY is as much due to his performance as it is to an clever visual that the computer uses to express its “emotions”. In an age when we’re used to communicating in the emotionally stifling media of texting and instant messaging, seeing a computer make use of the same cutesy little emoticons in the place of body language and empathy is surprisingly effective.

The relationship between Sam and the computer ends up being almost as fascinating as the one between Sam and his clone, and its exact meaning is one of the many things you’ll continue to think about after you leave this film.

Moon‘s dialogue is rich and concise, conveying exactly what it needs to and not a bit more. The film explores all of the questions I mentioned above (to name a few), but does so in a subtle way, and relies on its audience to answer them on their own time. Even the very last line of the film, a half-garbled radio transmission that plays as the credits begin to roll, conveys a fascinating idea. And that’s what you’ll get with this film. It’s for people who love big ideas. It is a welcome return to true sci-fi, and showcases one of the best performances of the year.