It’s easy enough to take Moon at its, well, surface and dismiss it as a simple if novel sci-fi trifle. But Duncan Jones’ directorial debut will likely leave you with questions that linger long after the credits roll. It’s a stick-to-your-brain-er. And, unlike too many what-just-happened films, it actually makes sense upon further examination.

Jones, the son of David Bowie, conceived the story and passed it along to another freshman, Nathan Parker, to flesh out. Moon somewhat unabashedly borrows—or pays homage to?—its predecessors, most notably Stanley Kubrick’s 2001: A Space Odyssey. Here, GERTY, voiced by Kevin Spacey with a sometimes-humorous emoticon display, is the film’s HAL, and both films share a sense of eerie foreboding. Though when you’ve got one man and a machine inhabiting a space station with no one but each other to talk to, perhaps the latter is inevitable.

That man is Sam (Sam Rockwell), an astronaut who’s committed to spending three years mining the moon’s surface for an energy source that could solve Earth’s crisis. When the film starts, he’s got only two weeks left before he returns to his wife, Tess (Dominique McElligott), and their toddler daughter, whom he periodically gets to visit via video feed. But then things start get nutty. Sam has visions, most notably of a woman who appears out of nowhere and disappears just as quickly. He sees himself in dreams. And then, after a minor crash during a lunar outing—his vehicle is adorned with hanging stuffed dice, one of the film’s many sly displays of wit—and subsequent period of unconsciousness, he really sees himself. It’s not a hallucination; it’s a clone. A chicken-and-egg argument and general feeling of animosity follows.

You’d think that 90-plus minutes of nice Rockwell talking to angry Rockwell, punctuated by conversations with the increasingly evasive GERTY, would get pretty dull—particularly when there’s no scenery except the done-before white, clean lines of the space station or blue-gray rubble of the moon’s surface. (Admittedly, though, the effects are pretty impressive given the film’s small budget.) And the why of the clone issue isn’t initially all that interesting, either, seeming more like a plot twist for its own sake.

But the filmmakers have a deeper conspiracy up their sleeves, one involving false memories, preprogrammed video calls, and, naturally, the likelihood that if there are already two Sams, there are probably more. Meanwhile, the first Sam starts physically and mentally falling apart. And that’s when the film really pulls you in. There may not be anything original about Moon’s essential elements—clones, evil A.I.s, isolation in space, yawn. Tying them to the issues of energy consumption and corporation coverups, however, give the been-there details a new spin. Moon is ultimately a boost to the usually disappointed sci-fi genre, and Jones is a director to watch.