The film received mixed reviews. , it holds a 38% approval rating on aggregate review site
Rotten Tomatoes, based on 66 reviews, with an average score of 4.89/10. The site's main consensus reads "An earnest attempt to parody campy 1950s sci-fi films, Alien Trespass eventually loses its charm among tedious dialogue and cheesy special effects." Film critic
Roger Ebert gave the film two out of four stars and felt that the film was, "obviously a labor of love. But why? Is there a demand for cheesy 1950s sci-fi movies not met by the existing supply? Will younger audiences consider it to be merely inept, and not inept with an artistic intention? Here is a movie more suited to ComicCon or the World Science Fiction Convention than to your neighborhood multiplex". In her review for
The New York Times, Jeannette Catsoulis described the film as "a charmingly sentimental but ultimately pointless hommage to the sci-fi classics of yesteryear". Betsy Sharkey, in her review for the
Los Angeles Times, felt that "there is attention to detail throughout this film, and it's clear that Goodwin loves those old sci-fi movies – maybe a little too much. While
Alien Trespass stays true to the era and the genre, it forgets that its mission in this galaxy is not merely to pay tribute but to entertain".
IGN mixed praise and complaint, saying, "
Alien Trespass was clearly made with the intention to both emulate and satirize the classic B-movie sci-fi films of the 1950s – and not in a semi-serious Roland Emmerich kind of way, but in a careful replication of the era, complete with flying saucers, sub-par effects and some overly hammy acting. The problem, unfortunately, is that the movie aims to have it both ways and quite simply can't, straddling the cinematic line for about 10 minutes before falling gracelessly into its own confused voice." The reviewer added, however, "If
Alien Trespass succeeds in any regard, it's simply in creating a world that feels, at least in spirit, like an authentic – or perhaps nostalgic – depiction of the period. The sets, the costumes, the cars, the vocal affectations – neither parody nor slavish recreation. And the visual effects, despite being created by CG to appear properly low-tech, feel enough like large plastic creatures and saucers on strings to blend seamlessly into the spirit of the piece. All in all, the design of the film is considerably more effective than its substance." In his review for
The Boston Globe,
Ty Burr felt that the film was superior to
Monsters vs. Aliens, saying "There's more simple joy to be found here than in all of
DreamWorks' 3-D extravaganza, though – a pleasure that comes from laughing at the movie and with it at the same time".
Entertainment Weekly gave the film a "B+" rating and Lisa Schwarzbaum praised its "warm tone, along with the picture's bright, saturated, anti-CGI look, is a welcome respite from jokes, irony, and the postmodern malaise of know-it-all-ness".
Gary Westfahl, a reviewer of
science fiction, found this film and
The Man from Earth (2007) to be overlooked gems of the genre. He hopes that they can both eventually be rediscovered. He found the film able to capture the "klutzy charm" and the true virtues of the 1950s science fiction films. ==See also==