There’s a brutally efficient energy to this war movie recreating with 4K digital clarity a real incident involving US special forces on a chaotically failed mission in Iraq in 2006, co-directed by Alex Garland and former US Navy Seal Ray Mendoza; the latter was a military consultant on Garland’s previous film Civil War, and reconstructed the events from his own memories and those of his comrades. It is a visceral, immersive, often skull-splittingly loud film; real-time action with a found-footage aesthetic, featuring opaque technical dialogue and eerily ice-cold quiet moments seen from the aerial reconnaissance computer screen, with murmuring detached voices audible.

Warfare really does show the punishing boredom of a soldier’s life. But it is weirdly obtuse and self-congratulatory, the shock of its ending softened by some bizarrely misjudged material over the closing credits, showing pictures of the actors next to their real-life counterparts and even showing home-movie type footage of these soldiers now beamingly hugging the stars. It’s as if Garland and Mendoza finally felt the need to pull out to reveal the bigger picture, and found only a reality TV show.

In 2006, an American unit with two Iraqi scouts is moved under cover of darkness into a residential area of Ramadi province, ruthlessly taking over two apartments and ordering the terrified civilian occupants to stay in a bedroom and keep quiet; they knock a discreet hole in the wall and set up a sniper-surveillance position from which to give cover for a ground-troop operation. The team includes Ray himself (D’Pharoah Woon-A-Tai), commanding officer Erik (Will Poulter), sniper Elliott (Cosmo Jarvis), MacDonald (Michael Gandolfini) and Sam (Joseph Quinn). While Elliott does nothing but gaze through his gun-sight, minutes and hours of tense silence drag by as the men, with muscular professionalism, stay at a level of hyper-alertness. One drags his fingertip across a dusty surface, looks at it, looks up, drops his hand, thinks about something else. There is no old-school stuff about the guys in a quiet moment looking up at the stars and talking to each other about what they’re going to do when the war is over.

But when Elliott has to lay his sniper rifle down for a moment and stretch his legs, a less experienced and less competent guy has to take over and fails to take out a jihadi with a weapon across the street. The insurgents are close by and the unit is in danger; they lose air cover, the tank that was supposed to be taking them away is blown up and there is carnage. One man even slips on the fragment of a severed leg in the road scrambling back into the apartment building after the aborted evacuation.

In some ways, Warfare is like the rash of war-on-terror pictures that appeared 20 years ago, such as Kathryn Bigelow’s The Hurt Locker or Nick Broomfield’s Battle for Haditha, or indeed Brian De Palma’s interesting, underrated film Redacted. But Warfare doesn’t have the anti-war reflex and is almost fierce in its indifference to political or historical context, the resource that should be more readily available two decades on. There is almost no conventional narrative progression: Erik gets rattled and has to cede command to someone else, but it makes no real difference to the dramatic shape, the white-noise blizzard of chaos. Similarly, the two Iraqi scouts become scared when they realise that they are to be the first out of the door for the planned evacuation, but there is no real tribal division between them and the Americans. Periodically the men will radio for a “show of force” to keep the jihadis at bay: a fighter plane whooshing terrifyingly low along the street leaving behind an eardrum-pulverised silence which scours the screen of thought.

And those civilians? They have an odd role to play in those weird photos over the final credits. Some of the real-world soldiers have their faces blanked out, presumably due to ongoing security considerations. But the film also shows a picture of an Iraqi family, evidently the occupants of the house, with their faces blanked out as well. Because … Garland and Mendoza tried to locate these people and ask for their memories too? And were unable to find them? Maybe. But they just remain blank – and irrelevant. The movie is its own show of force in some ways, surely accurate in showing what the soldiers did, moment by moment, though blandly unaware of a point or a meaning beyond the horror.