Iron Sky

This much-rumoured independent movie has been in the works since 2006, and is improbably billed as a Finnish-German-Australian co-production. It's also unusual for being a project that grew out of the online self-supporting film-making community, Wreck-a-Movie.

The premise is almost irresistible, and is summed up in the marketing tagline: "In 1945 the Nazis went to the Moon. In 2018 they're coming back." The action commences with the American "Liberty" space mission landing on our nearest galactic neighbour, but it transpires that it's essentially a promotional visit to boost the re-election campaign of the American president (who isn't named, but is played as a ringer for Sarah Palin by Stephanie Paul).

Having unfurled huge presidential banners from their landing craft, with a picture of the Prez under the slogan "Yes we can", the pair of astronauts go for a lunar stroll, but down in the craters on the moon's dark side, all is not as expected. They stumble across a vast mine digging for the priceless fuel Helium 3, but have barely had time to absorb the shock when a motorcyclist in Nazi uniform roars up and shoots the first astronaut. The second, James Washington (Christopher Kirby), is taken prisoner.

As advertised, Hitler's acolytes did indeed find refuge on the Moon as World War Two reached its grisly climax, and now they're ensconced in a vast swastika-shaped complex from which the latest Führer, Wolfgang Kortzfleisch (Udo Kier, pictured above), aims to return to earth and establish the Fourth Reich. To help him, he has the fanatical and square-jawed Klaus Adler (Götz Otto), who plans to unite with the comely Fräulein Renate Richter (Julia Dietze) to produce impeccable Aryan children.

The Department of Racial Purity, he tells her, has confirmed that they're a 97 percent genetic match. Thanks to Renate's father, mad scientist Dr Richter (Tilo Prüchner), the Moon Nazis have developed an array of flying saucers and enormous space-zeppelins with which to transport themselves back to the Fatherplanet. His super-secret weapon is the vast Battleship Götterdämmerung, a kind of interstallar Bismarck.

All of this is sort of entertaining, though it's never clear whether the Nazis are supposed to be utterly despicable or merely burlesque, Mel Brooks-style Nazis. Toying amateurishly with National Socialism also incurs some bad-taste penalties. There's a bit of queasy sport with the fact that astronaut Washington is black, which the Nazis find so alien that they inject him with Richter's albino serum to make him acceptably, and perhaps offensively, white. There are also flabby technology jokes, like the way Washington's smartphone is so powerful that it can control the Götterdämmerung. When the battery goes flat Adler declares that he will return to earth with Washington to round up more supplies of phones (he ends up bringing back an iPad).

As the plot unwinds, hopes of being overwhelmed by gales of satirical hilarity recede swiftly into the distance. Events occur and characters are introduced, but none of these things feel connected to one another. The resolution that director Timo Vuorensola appears to be fumbling towards is that contemporary American politics is the same as Nazism, with the USA crudely portrayed as a warmongering imperialist monolith, while the Palin figure gleefully adopts Adler and Renate (pictured above) as uniformed cheerleaders for a kind of strength-through-joy initiative.

"The world is sick and we are the doctors," declares Renate. "We are here to make the world healthy once again." Wagner's Tannhäuser overture plays in the background, depressing evidence of the humourless literal-mindedness that ultimately dooms Iron Sky to irrelevance. Renate's final passionate union with a restored-to-blackness Washington is served up as a refutation of Nazi racial ideology, a gambit so crude that it might have made even Joseph Goebbels blanch.

Still, on the upside, the special effects are remarkably good considering the flick was made on a $9m budget, with some excellent sequences of flying saucers whizzing over Manhattan and an impressively large-scale space battle. What they really needed was another couple of million to spend on the script.

• Iron Sky is screening on 23 May in key cities before being rush-released on DVD

Watch the opening four minutes of Iron Sky