A low-key, semi-improvised relationship drama, with added space-monsters, Gareth Edwards’ “Monsters” is pretty much pre-designed to push all my cinema-going buttons; even before taking into account the seductive back-story of its shot-on-the-fly, ultra-low-budget (apart from the thousands of £££s worth of computer equipment) production process. I was relieved, therefore, when it turned out actually to work spectacularly well on a number of levels. The perfectly named Scoot McNairy and Whitney Able play the cynical photo-journalist and leggy blonde heiress (cf “Roman Holiday”, “It Happened One Night”) struggling to make their way across a Mexico infested with huge, octopus-like alien creatures, contending with all sorts of Hollywood screenwriting bullet-points along the way (the ticking clock, overcoming obstacles, emotional growth etc). There’s much political subtext, both subtle (neurosis over border control), and unsubtle (the American response to the crisis is to bomb the aliens, killing mostly civilians; and the whole problem is America’s fault anyway, obviously); and the cinematography is highly impressive without being showy enough to distract from the engaging performances and tense narrative. There are longueurs, although these are mostly spent waiting for bad stuff to happen; the pay-off comes when Edwards opts for a bravely subtle ending rather than an explosive climax. A skilful manipulation of clichés to create a thing of beauty.