The premise is stark: either they eliminate the alien threat or face their own demise. It's set in what was then the future, 1973, and depicts the first human mission to Mars that has run into trouble. When a rescue crew arrives at the damaged spacecraft, they discover only one person alive – Col. Edward Carruthers, the expedition’s leader. He insists an alien being was responsible for his team's fate, but this explanation is received with doubt as he recounts what happened... The film had largely faded from view until Ridley Scott’s highly successful *Alien* in 1979 drew attention to its plot parallels. Now, *It! The Terror from Beyond Space* is appropriately considered among the finest low-budget science fiction films of the 1950s. It's true that it has some awkward moments and the alien’s appearance—a man in a rubber suit—isn’t exactly a display of brilliant filmmaking, but its underlying scientific concepts and the feeling of being trapped contribute significantly to overcoming any shortcomings due to budget limitations. The film takes place aboard a classic V-2 rocket ship, and Edward L. Cahn directed it with a script by Jerome Bixby. Bixby had previously worked on projects like *Star Trek*, *The Twilight Zone*, and *Fantastic Voyage*, so the writing was in capable hands. While the basic storyline doesn’t present anything entirely new, there's more to the film than initially apparent. As for the alien itself? It clearly shows the constraints of its limited budget. Ray "Crash" Corrigan portrays it as a clumsy, grunting creature that is shown too much during the latter portion of the movie. However, thanks to Kenneth Peach’s restrained black and white cinematography, the alien remains an effective presence as it hunts its victims through the ship's metal corridors. The cast consists of typical performers from “B” movies, with Marshall Thompson and Shirley Patterson delivering solid performances. Grant Whytock in editing also deserves recognition for keeping the film free of unnecessary scenes. It’s a tense and unsettling little thriller that anyone interested in the heyday of low-budget science fiction and old-fashioned monster movies should watch. 8/10

Source on TMDB