Lean, ambitious, unsentimental, overwhelmingly guy-centric, unmodulated and bombastic, Christopher Nolan’s World War II epic “Dunkirk” showcases the best and worst of the director’s tendencies. The best win out and the worst recede in memory when you think back on the experience—provided that you want to remember “Dunkirk.” This is a grueling movie, and it’s supposed to be. Less of a war film and more of a disaster (or survival) picture, it’s an ensemble work that chronicles the evacuation of English soldiers who got trapped in the harbor and on the beaches of Dunkirk, France, in late May and early June of 1940, and wondered if they’d starve to death before the Germans could kill them.If you were to make a list of every phobia you can think of, you’d have to tick off a lot of boxes after seeing this film. Fear of heights, fire, drowning, confined spaces, darkness, abandonment—you name it, it’s represented in cinematographer Hoyte van Hoytema’s nightmarishly clear images. And if you see the movie in one of the handful of theaters showing it in 70mm IMAX format, the experience will feel even more constricting and oppressive because of the shape of the screen. It’s close to the old-fashioned “Academy” ratio common to films made in cinema’s early decades: squarish, tall rather than wide. That means that when you’re in the cockpit of a fighter plane diving towards the sea, or running behind the shoulder of an infantryman running through a seaside village’s streets while German snipers fire on him, the idea of “tunnel vision,” a phrase many trauma survivors have used, becomes more immediate—something you feel rather than intellectually appreciate. The film will be shown in wider format in most cinemas, but I doubt this will lessen the overall effect: this is a pile-driver of a movie, dropping one visual or aural bomb after another without much in the way of relief, or even a pause to contemplate what it’s already shown you. To watch it is to feel beleaguered. This was a period in which German military power was ascendant and hope for the United Kingdom’s survival was starting to ebb. The story of Dunkirk has been told on film before, notably in Leslie Norman’s same-titled 1958 feature, and there have been no shortage of other films about unlikely battlefield rescues; but this one feels different, mainly because of how it’s made. Nolan, who also wrote the film’s script, drops you into the middle of the action from frame one and keeps you there. This is an ensemble movie that doesn’t just fail to delineate most of its characters through exposition but seems to take perverse pride in letting them scamper across the screen at flyspeck distance, getting lost amid crowds or hidden by smoke or sea water. Scenes often play out for minutes without audible dialogue, a rarity in commercial cinema made at this budget level; it’s even rare in Nolan’s own films, which tend to clarify narrative through massive verbal exposition dumps. Like a hyperactive cousin of Terrence Malick, who infused the combat picture with Transcendental philosophy in 1998’s “The Thin Red Line,” or Robert Altman, who painted microcosmic panoramas of civilization in such films as “Nashville” and “Short Cuts,” “Dunkirk” treats every English soldier on that beach and in assorted nearby planes and boats as part of a single collective organism, less interesting for their personal details than for the role they play in the drama of history, however large or small that may be. “Dunkirk” is what I like to call an Ant Farm Picture: it’s a portrait of a society, or a species, fighting for its life. It’s not terribly interested in the plight of individuals, unless they’re trying to save themselves or others. If you get confused about who’s who and what’s what from time to time, you can rest assured that this is a feature of Nolan’s peculiar methods, not a bug (pun intended). Tom Hardy plays a fighter pilot trying to blast German pilots out of the sky before they can strafe helpless soldiers on the ground and sink boats in the harbor. He has maybe a dozen lines and spends much of the film behind a mask (just as he did in his last collaboration with Nolan, “The Dark Knight Rises”) but makes a strong impression by treating the character as the sum total of his actions. Mark Rylance plays a civilian with two teenaged sons who is determined to pilot his small yacht to Dunkirk and rescue as many people as he can; there are a lot of these sorts of captains bobbing around near Dunkirk, and their ultimate organization into one of the twentieth century’s boldest non-military flotillas is as inspiring as you imagine it to be. A trio of soldiers, one of whom is played by Harry Styles, rushes from the town to the sandy beach and out onto a long dock that stretches into the ocean; this is the only way that big boats can get somewhat close to shore. The would-be passengers pray that they can load onto a ship and get out of there before more German planes swoop in and kill them with bombs or machine gun fire. Many don’t get their wish. Some of the characters, including Hardy’s Farrier and Rylance’s Mark Dawson, are given names in the script. Many more are identified only by their general appearance or actions, such as Cillian Murphy, known only as “Shivering Man”; he’s pulled from the icy sea by Rylance’s captain and strongly urges the crew to sail away fro Dunkirk, not toward it.The film has its stumbling blocks. One is the persistent anonymity of the characters; just because a gambit is part of the film’s design doesn’t mean it works, and there are moments you may wonder whether treating supporting characters as something other than glorified cannon fodder might have resulted in a film that’s as emotionally powerful as it is technically impressive. Another is the score, by Hans Zimmer, a Jungian din of booming drums, bum-vibrating synth chords, and cawing string effects that loses much of its power by refusing to shut up, even when silence or ambient war noise might have been just as effective, or more so. I was more on-the-fence about the movie’s narrative construction, but once the visceral impact of the film faded, it was there that my mind wandered. Like most of Nolan’s films, this one is fascinated by the relative perception of time—an idea that’s emphasized in the cross-cutting of Lee Smith, who edited all of Nolan’s film, including “Interstellar,” which is very explicitly about that concept. “Dunkirk” tells us in opening titles that one major story takes place over a month, two others during the course of a week, and so on; then the movie hops between them in ways that compress and expand time for poetic effect—making, say, a plane’s run that probably took thirty seconds seem to take as long as a rescue operation that might’ve required hours. One could make a case that this amounts to over-intellectualization of a strong, simple tale, but that’s been Nolan’s modus operandi from “Following” and “Memento” onward, and I’d be lying if I said it didn’t consistently fascinate me, even if a particular movie isn’t really doing much for me. It has often been said that the experience of drama wreaks havoc with one’s perceptions of time, and this is one of the few movies I can think of that considers that notion over the course of a whole feature film, not just in particular, self-contained sequences. The backbone of Zimmer’s score, appropriately, is the ticking of a clock. If somebody were to ask me if I liked this movie, I would tell them no. I hated parts of it and found other parts repetitious or half-baked. But I admired it and have been thinking about it constantly since I saw it. Even the aspects of “Dunkirk” that didn’t sit right with me seemed all of a piece. This is a movie of vision and integrity made on an epic scale, a series of ideas and propositions dramatized with machinery and bodies. They don’t make them like this anymore. Never did, really.