Updating the Beck/Fernandez "Lonely Hearts Killers" 1951 case (this is a fourth feature-length adaptation) for the Match.com era, Fabrice du Welz's serial-murder jolly doesn't quite dramatically press its central relationship enough to prevent the film from devolving at the last into a default bloodbath. But it's disturbingly credible for a long time, its expert camerawork – all bifurcated faces and heaving pores – seeding the air with claustrophobia around Almodóvar regular Lola Dueñas and Laurent Lucas' dysfunctional union. Apparently the latest in the line of divorcees duped by Lucas' Bogart-loving sociopath, it's Dueñas who turns out to be the lady killer – as if Ben Wheatley's Sightseers had been drained of every corpuscle of comedy, apart from the blackest ones; with her wracked, martyrish grin, she is a kind of hellish warrior-saint for true love. Du Welz never wants for elan (at one point giving his killer a Magnolia-style song before some butchery) but like his characters, he is constantly on the brink of losing composure, and finally does.