Dunkirk

Action-adventure films unfold as a series of waves, setting up characters and situations before introducing a trickle of intrigue to keep their viewers interested. Levity is important too, a smile here or there helps to keep the characters feeling human, extra necessary if a writer is pushing too hard in a structural direction, exposing the on-screen action as a series of ruthless data points. A well-written character then will allow a viewer to simmer in their company, charting a growth in their gradual response to the unfolding mayhem.

This is, in part, the strength powering television streaming's current golden age - personalities are afforded the space, time and storylines required to simulate evolution. Running a scant 106 minutes, Dunkirk doesn't have the luxury of time, it isn't able to slowly pick its characters apart to see what makes them tick. Instead it takes a series of easily understood archetypes - the teenage soldier, the father, the ace - then endangers them. With not a second to spare, writer-director Christopher Nolan explores his characters in their minute-by-minute response to this sustained, mounting terror.

Heroism, if and when it manifests, is not expressed through triumph. Success is measured only in the decision to continue struggling, to stare directly into calamity and keep heading towards it. The rout at Dunkirk and the subsequent evacuation are the perfect scenarios to draw out these kind of details. Running time doesn't need to be dedicated to any kind of overarching exposition, beyond a clipped opening brief. Likewise characters aren't required to do anything more complicated than survive. Dire situation in place, Nolan can knuckle down on the finer, more expressive moments that a locked on-spec cinema experience can provide.

Nolan's thundering insistence that his film be viewed under very specific conditions makes more sense when we see how he uses the verticality provided by IMAX's 1.43:1 frame. With The Dark Knight the effect was perfunctory, arriving infrequently to stress the towering, monumental scale of the city at the centre of Batman's mission. On Dunkirk Nolan uses the elevated ratio to create images that expand in every direction, depicting unconquered, threatening space above and below his subjects.

These shots, working in concert with gun reports that hit like cannons and Han Zimmer's clattering approximation of a heart-attack, congeal into an ever-present sense of doom. Death can come from any and every direction. This effect is further accentuated by Nolan's decision to fold the Nazi menace into the environment itself, never breaking from his subject's limited, blinkered perspectives. The presence of U-Boats, for instance, isn't established through miniature coverage or a prowling, CG effect, that would break the carefully calibrated illusion.

Viewers are quickly conditioned to expect the promenade strafing runs, to know that making it on to a fleeing boat does not guarantee safety. Dunkirk pulses with this anxiety, a film primed to cascade into full-on horror at a moment's notice. The scope for danger is exacerbated by the tall frame; a towering expanse primed to overwhelm and consume the tiny, vulnerable figures limping across the frothing, voided landscapes.

If the pace ever threatens to slacken or, God forbid, provide a gasp of breathing room, the film hurtles off to another temporal point where jeopardy can be piled on until the next natural break. The three stories - The Mole, The Sea, The Air - collide and interconnect frequently, working in service to their own individual dramas and a wider perspective on the unfolding nightmare. Nolan doesn't hold back these convergence points either, we often see disastrous results long before any of the boys summon up the courage to instigate them. These shifting, even clashing viewpoints are another tool used to express the terrifying indifference of collapsing, ruptured machinery.