Tom Shankland's impressive debut feature stars Stellan Skarsgård as a hard-boiled New York detective hunting down a serial killer who carves a series of equations (hence the title - that's 'WΔZ' rather than 'Waz') into victims' bodies. It becomes apparent that the symbols represent the so-called Price equation - theoretical proof that every animal's strongest, overriding instinct is for self-preservation; the vengeful killer is testing the supposition that you will kill the person you love the most in order to save yourself. While the plot twists rarely come as a surprise, the film's grimy feel and effective pacing, and a gripping - if occasionally rather over-exaggerated - central performance by Skarsgård, make this a genuinely thrilling venture into Se7en territory, despite the unfortunate silliness of the title.