Bombs fall onto a packed pier, the explosions marching steadily towards you as the deep bass of the detonations hammer you back into your seat.

The whip-crack sounds of rifle fire threaten to rupture your eardrums while startling you as much as they do the hapless soldiers on screen fleeing for their lives from an unseen enemy.

Machine-gun fire segues into a driving soundtrack that segues into the scream of German dive-bombers, the orchestral becoming so organically woven into the aural that you are hard pressed to tell the two apart. (That the score is by Hans Zimmer, whose last few efforts have been mostly excess and bombast, makes it all the more remarkable.)

This goes beyond director/writer Christopher Nolan just supervising the sound editing and scoring – it’s a filmmaker thrusting his arms into the mix right up to his elbows and kneading, teasing, moulding everything into the perfect shape.

And that’s just the audio component.

In Nolan’s World War II saga Dunkirk, it helps to plunge the viewer into the harrowing survival struggle of hundreds upon thousands of Allied troops as they wait helplessly on a beach in France for rescue.

Two decades ago, Steven Spielberg redefined the war epic with Saving Private Ryan, employing sound distortion and buckets of gore and guts to give an authentic (and much-copied) feel of being there on D-Day when the Allies (mostly American) invaded Nazi-occupied Europe.

Now, Nolan logs another genre-defining moment in retelling the unceremonious Allied (mostly British, the Yanks weren’t in the war yet) departure from Europe in 1940 with a marked de-emphasis on conflict and combat – except for some superbly edited, nailbiting dogfights – and he does so with a minimum of blood.

Dunkirk

No, no, I said look ahead or down – figures, there’s always got to be one joker on the set who can’t take direction. Photos: 20th Century Fox

It’s all about the human drama, on a level so staggering that you can feel it even when Nolan chooses to focus on little pockets of the unfolding ordeal.

Juggling three converging timelines, each on a different scale – one takes place over the course of a week, another over a day, the last over just one hour – he masterfully brings them together in such a virtuoso manner that you want to stand up and applaud him as much as the valiant civilians who sailed to the stranded soldiers’ rescue.

A Christopher Nolan film is always challenging in some way, whether it’s your moral compass (The Dark Knight), your imagination (Inception) or your patience (The Dark Knight Rises, Interstellar).

Here, it’s a pretty simple challenge: just keep up.

We don’t get much of an insight into the characters, and in many cases we don’t even know why we should care about them. Yet care about (some of) them we do, whether it’s Cillian Murphy’s shell-shocked (read: PTSD-suffering) survivor, or Mark Rylance’s grimly determined civilian sailor, or One Direction-er Harry Styles’s largely generic soldier trying to make it off the beach along with other desperate young men played by Fionn Whitehead and Aneurin Barnard.

Tom Hardy’s brave airman and Kenneth Branagh’s steadying presence as a naval commander in the thick of the evacuation are perhaps the closest Nolan comes to war movie tropes, but even these familiar types are effectively utilised at just the right moment.

The stakes at Dunkirk were high, but let your attention slip even a moment and you’ll miss the subtle explanation in the dialogue. With nearly 400,000 men committed to France and Belgium to stop the German advance, the British needed to get them back – or be forced to capitulate to Hitler.

And we see it in the relentless way the Germans bomb, torpedo and shoot the troops, even on medical frigates, simply because every dead or captured soldier brings England’s surrender that little bit closer.

By keeping the German attackers and the French defenders out of the frame, and focusing strictly on the primal impulse to survive, Nolan’s film creates a noble and almost heroic aura around an ignominious defeat.

We don’t think any less of the exhausted and bedraggled troops even when they make some questionable calls in the name of survival, or inadvertently cause harm to those trying to save them.

Dunkirk does not put us in a position to judge but, through the immersiveness of Nolan’s narrative and technical achievements, it puts us in a position to understand.

Dunkirk

The lads were a tad upset that the fates took the term ‘left high and dry’ too literally.


Dunkirk

Director: Christopher Nolan

Cast: Fionn Whitehead, Harry Styles, Aneurin Barnard, Mark Rylance, Tom Hardy, Cillian Murphy, James D’Arcy, Kenneth Branagh