Critical reception
Moon was generally well received by critics. On the review aggregator website Rotten Tomatoes, 90% of 195 critics' reviews are positive, with an average rating of 7.5/10. The website's consensus reads: "Boosted by Sam Rockwell's intense performance, Moon is a compelling work of science-fiction, and a promising debut from director Duncan Jones." Metacritic, which uses a weighted average, assigned the film a score of 67 out of 100, based on 29 critics, indicating "generally favorable" reviews.
Damon Wise of The Times praised Jones' "thoughtful" direction and Rockwell's "poignant" performance. Wise wrote of the film's approach to the science fiction genre: "Though it uses impressive sci-fi trappings to tell its story – the fabulous models and moonscapes are recognisably retro yet surprisingly real – this is a film about what it means, and takes, to be human." Duane Byrge of The Hollywood Reporter applauded screenwriter Nathan Parker's "sharp [and] individualistic" dialogue and the way in which Parker combined science fiction and Big Brother themes. Byrge also believed that cinematographer Gary Shaw's work and composer Clint Mansell's music intensified the drama. Byrge wrote: "Nonetheless, 'Moon' is darkened by its own excellencies: The white, claustrophobic look is apt and moody, but a lack of physical action enervates the story thrust." The critic felt mixed about the star's performance, describing him as "adept at limning his character's dissolution" but finding that he did not have "the audacious, dominant edge" for the major confrontation at the end of the film. Roger Ebert, giving the film three and a half stars out of four, wrote:
Moon is a superior example of that threatened genre, hard science-fiction, which is often about the interface between humans and alien intelligence of one kind of or other, including digital. John W. Campbell Jr., the godfather of this genre, would have approved. The movie is really all about ideas. It only seems to be about emotions. How real are our emotions, anyway? How real are we? Someday I will die. This laptop I'm using is patient and can wait.
Empire magazine praised Rockwell's performance, including it in '10 Egregious Oscar Snubs—The worthy contenders that the Academy overlooked' feature and referred to his performance as "one [...] of the best performances of the year". Rolling Stone magazine ranked the film at number 23 on their Top 40 Sci-Fi Movies of the 21st Century, finding that "Duncan Jones' debut feature keeps you wondering whether its hero – played by an on-point Sam Rockwell – is losing a battle with what appears to be his "double" or if he, is, in fact, losing his mind [...] this sci-fi indie does a helluva lot with very, very little". Digital Spy said it was an "incredible low-budget science fiction movie", opining that Jones' direction of the film "brilliantly explores ideas of identity while mixing in some practical VFX spectacle to boot. This is perhaps one of the best sci-fi films of the 21st century".
A. O. Scott, chief film critic for The New York Times wrote that Jones directing "demonstrates impressive technical command, infusing a sparse narrative and a small, enclosed space with a surprising density of moods and ideas". Scott said that like most of science fiction, the film "is a meditation on the conflict between the streamlining tendencies of technological progress and the stubborn persistence of feelings and desires that can't be tamed by utilitarian imperatives", while also asserting that "the film's ideas are interesting, but don't feel entirely worked out [...]the smallness of this movie is decidedly a virtue, but also, in the end, something of a limitation". Moon also received positive reviews at the Sundance Film Festival.