Socialist realism and science fiction aren’t especially compatible. That is to say, historically concrete representations of reality may be admirable, but Them! lived and died by giant radioactive ants. As a result, the films showing as part of the National Gallery of Art’s “Journey Through the Russian Fantastik” are the midnight movies that only communism could make. The sci-fi and fantasy auteurs of the West may have repackaged Cold Warnera American fears into B-grade titillation­, but the Soviet imagination was trapped behind an iron curtain of Politburo dictates. In the case of 1962’s The Amphibian Man (at 2:30 p.m. Saturday, Sept. 8), those constraints chafed. Awkwardly literal, unexpectedly tragic, and clunkier than a rusty Volga, this story of the gill-fated love affair between a handsome yet amphibious socialist and the wife of a capitalist pearlmonger was the party-line toeing, Khrushchev-era equivalent of Titanic. But filmmaking that operated outside market demands did have its advantages. No American studio would ever have greenlit a project like Andrei Tarkovsky’s visionary 1979 film Stalker—which spends 163 minutes following three men as they meander through a post-apocalyptic wilderness pondering metaphysics. Nor would U.S. audiences have appreciated a summer blockbuster like 1988’s Zero City, in which an air-conditioner repairman travels to an absurdist Soviet bureaucracy where he is served a cake baked in the shape of his own head. The series runs to Sunday, Sept. 30, at the National Gallery of Art’s East Building Auditorium, 4th St. & Constitution Ave. NW. Free. (202) 737-4215; see Showtimes for this week’s films; see nga.gov/programs/film.shtm for a complete schedule.