The Silence of Lorna, Jean-Pierre and Luc Dardenne, 105 mins, 15<br>To Get to Heaven First You Have to Die, Djamshed Usmonov, 95 mins, 15

This migrants' tale of manipulation and need is a rare dip in form from the Dardenne brothers

Consider this column a tribute to the great American film critic Manny Farber, who died earlier this year. In an influential essay of 1962, Farber proposed a distinction between what he called "white elephant art" and "termite art".

You can imagine what a white elephant film would be: lumbering, academic, sated on its own prestige, earnestly aspiring to masterpiece status. Clint Eastwood's new Changelingis a prime example. Expect to see whole herds of white elephants thundering by in the coming Oscars season.

For Farber, the real action lay with the sleeves-rolled pragmatism of termite artists who, as he put it, "have no ambitions towards gilt culture but are involved in a kind of squandering-beaverish endeavour that isn't anywhere or for anything." You might think of termite cinema as the work of film-makers who don't bully the viewer with their mastery, but just do what they do, in their own cinematic language, usually out on the margins.

Exemplary current termite film-makers are the Belgian brothers Jean-Pierre and Luc Dardenne; winners twice over of the Palme d'Or in Cannes, they may be the most unfussy directors ever to grab that award. The Dardennes burrow away making small, hyper-concentrated realist dramas in a tiny corner of the world – usually, a few streets of Seraing, an industrial town near Liège – yet they contrive to make that microcosm yield vast insights into the business of everyday survival. Few film-makers have the knack of taking such seemingly unpromising material – spare, Loachian anecdotes about underprivileged people hustling to get by – and applying their measured canniness to squeeze out the maximum emotional and social resonance.

The Silence of Lorna is not prime Dardennes – it's no Rosetta or The Child. It still recognisably has their intensely attentive touch, with Alain Marcoen's camera often hanging close on the actors' collars. But the brothers try new narrative tricks, and the result isn't entirely happy. Lorna (Arta Dobroshi), a young Albanian woman living in Liège, has married a young heroin addict in order to get Belgian citizenship. The plan is that he'll eventually overdose, leaving Lorna free to move on – which involves a prompt marriage for money to a Russian, so that he too can get a passport. (Who knew the world wanted to be Belgian?)

Lorna isn't as nearly as silent as the title suggests, but she's certainly reserved; it's hard to guess which way she'll turn at any point. When we first see her with her needy husband-of-convenience Claudy, she seems hard as nails, grimly in control. Then, against all expectations, she starts showing compassion towards him. And still things don't go as we expect. What's distinctive about this film – it's a new strategy for the Dardennes – is that twice it significantly wrongfoots us. The first time it happens, a major event takes place – off screen, without any comment – and we're simply left to take it in and get used to it. There's no rhetoric wasted here, and no lachrymose score to tell us how to feel.

The film's other major turnaround affects the way we perceive Lorna – who, far from being a cold-blooded user of people, turns out to be vulnerable and troubled. This leaves the denouement floundering in waters where the Dardennes don't seem comfortable: it's hard to know whether things are taking a dream-like turn, getting mythical or metaphysical on us. By that point, the film is so laden with narrative turns that the famous Dardenne simplicity (their 2002 film The Son could have been summed up in 20 words) finally seems squandered.

One reason the film doesn't quite work is Kosovan actress Dobroshi, who comes across as flat, sullen, opaque rather than tantalisingly inscrutable. She also has her thunder stolen by Dardenne regular Jérémie Renier, whose emaciated Claudy is whiny, child-like, crackling with deluded energy and altogether note perfect. If Lorna is below par, let's hope it's a transitional film for the Dardennes. Still, you know you're in the hands of masters, even if they've dropped the ball.

The week's real termite discovery is a film from Tajikistan by Djamshed Usmonov, whose much-acclaimed Angel on the Right I'm sorry I missed. To Get to Heaven First You Have to Die digs away at its leisurely route for a good half-hour before we remotely know where it's heading. It starts off as downbeat naturalism, as a young man (Kurched Golibekov) consults a doctor about his erection problems. Then Kamal – we only learn his name 45 minutes in – is on a train, and hovering with calf-eyed eagerness around a young woman, who gives him a rather maternal brush-off.

In the city, Kamal starts trailing other women, and we're still not sure how to take the film, or its hero. Will it be a poker-faced comedy of frustration? Is there something creepier to come? Or will this continue to be one of those cheerfully event-free art films? While it continues to be a film about nothing, To Get to Heaven... is a superb example of the genre, and brilliantly edited: there's a perfect sequence in which Kamal sullenly watches bus after bus arrive, hoping to glimpse the young Russian woman (Dinara Drukarova) he's taken a shine to.

Then something does happen – and sends the story spinning off on a new trajectory. The film also gets a fresh burst of energies from actor Maruf Pulodzoda – just one shot of whom signals bad news of the worst kind. Usmonov's film might have come across as brutish, macho and heartless, if not for the flat, uninflected style and the extraordinary presence of young lead Golibekov. His shy, impassive blankness makes the viewer ready to follow wherever the film takes us. At the end, we're not sure where things have come out, either; there's no moral, no comment, and it feels as if it's been a troubled dream. That's termite logic for you.