With ever more mainstream films succumbing to star casting and "what it says on the tin" storylines, documentaries have become the cleverest reason to spend an hour and a half in the cinema. Michael Moore might be as jumped-up and smug as those he sets out to parody, but at least his films have energy; and there have been more subtle delights in Spellbound, Super Size Me, Capturing the Friedmans and The Kid Stays in the Picture.
Which brings us to Czech Dream, a documentary set in Prague. It's of the Super Size rather than the Friedmans type - it's not a recording of events or people unrelated to the movie-maker, but a film of an idea. The idea is that of the directors, who take it to its ultimate conclusion. And, like Morgan Spurlock's anti-McDonald's film, Czech Dream's notion is a comment on contemporary consumerism.
We are told the premise right at the start. VIt Klusak and Filip Remunda, two scruffy film students, face the camera to explain that they are creating a fictional hypermarket called Czech Dream. They will promote it to the hilt, then see what happens on opening day. Will anyone turn up? And if they do, how will they react when they realise that what they thought was a new shopping enormo-drome is just some covered scaffolding?
Anyone who has worked with university students recently will know that they are obsessed with branding and advertising, with the manipulative tools of modern trade, and initially Czech Dream has that boo-to-the-man final dissertation feel. To seem more convincingly capitalist, the boys get their hair cut and slip into some Hugo Boss suits ("Hold the logo for ten seconds," says the Boss PR to the cameraman). They pose for enthusiastic photos, twinkling like real marketing managers. So far, so surface. It is when they engage an advertising firm, BBDO, that the film begins to lift. BBDO's head honcho, a chubby chap with kerayzee hair, really believes in his job, in its power and its ethics. He tells us that the Sistine Chapel ceiling was the world's first advertising campaign (for God), and there's an interesting sequence when Klusak tries to get the BBDO team to include the words "You won't go home empty-handed" in one of the ads. The agency workers revolt: "We don't tell lies," insists one.
Yet, of course, they are telling a whopper: not through their exact wording, but the lie is there, so huge that no one would believe it wasn't the truth. The advertising screams "Don't come, don't spend", but the slogans look like reverse psychology, and when they are blanketed across Prague - on billboards, bus stops and the fronts of trams - even the most sophisticated reader of modern publicity mores would find it hard to spot the scam.
Klusak and Remunda make TV adverts, too, and hire pretty girls to hand out promotional Czech Dream flyers outside other shops. So when opening day arrives . . . well, I don't want to spoil the end, but let's just say it is by far the most enthralling part of the film, not just for the footage, but for the feelings it engenders in the viewer. Do you think that what is happening is funny? Or exploitative? Does it make any point other than to highlight how susceptible people are to advertising? And don't we know that already?
The filming itself isn't bad - the directors have a nice eye for confrontation, though because they are often in front of the camera, the donkey work is done by their film-student friends. In fact, everyone is so keen to get the pictures that there are often too many cameras getting in each other's way. Still, it's the idea that is paramount, rather than the beauty of the shots. Though here, I think, the directors missed a couple of tricks.
In the Czech Republic, after the first western supermarket was opened in 1995, 125 hypermarkets were unveiled in five years; to compare, it took 20 years to build the same number in the Netherlands. But this salient fact is not found in the film, but in the accompanying PR literature, which seems a shame. Similarly, it becomes clear right at the end that the scam is interpreted by Czechs as a comment on their country's entry into the European Union; it is not clear why, until you know that there has been a huge government-sponsored advertising campaign to win public support for joining up.
But these are teeny niggles: after all, Czech Dream was made for Czechs, who know these things already. It is a testament to the documentary's success that it is being viewed by less well-informed westerners. This is a charming film that seems small but aims high with its questions and execution, and has a ghastly relevance that resonates across the world. Now then, I'm off to Ikea.
Mark Kermode is away