What hit me about halfway through Dunkirk is this: it’s not a war movie, it’s a horror movie. It has all the characteristics of an effective horror film. The enemy is unseen, doesn’t speak, and is barely named; yet it is omnipresent and apparently unstoppable. The protagonists are interchangeable, and secondary to the horror itself, which is the real main character. Danger comes to them from all directions, in many forms, the more menacing because it is unpredictable: bullets, bombs, torpedoes, water, fire, even the men’s own ships and docks. The protagonists turn on each other in their growing paranoia and shock. The scene where men are trapped inside a ship waiting for the tide to come in, for example, is a masterpiece of the horror genre. For my part, the constant threat of drowning that recurred throughout the movie was the most awful horror of all.