You can find many fawning reviews of Dunkirk. This is not one of them. I left at the two-thirds point.
The movie is gorgeously shot and staged. If you see it, see it on the biggest screen you can find. Thus ends the complimentary portion of this post.
What this movie needs is more miracle and less masturbation. Christopher Nolan managed to take one of the greatest stories in history and turn it into a referendum on his own narrative cleverness. I found it self-indulgent and shallow, and as his indulgences revealed themselves, I grew disappointed and irritated. This story does not need to be cool-i-fied with quick cuts and time-jumps. I suppose Nolan thought that since we know the ending, we needed mystery—specifically the mystery of WTF is going on, who are these translucently thin characters, is that music or did someone fill a washing machine with cats and push it down a flight of stairs, and why didn't they just tell the damned story?
My Erwin Rommel story is fourth-hand and possibly filtered through senility, so take this with a commensurately sized grain of salt.
When I was a kid, I heard Woody Hayes give a commencement address. In addition to being a football coach, he was a history professor. The latter was his great passion, and that's what he spoke about that day. And spoke. And spoke. Woody was quite old at this point.
Woody had met Manfred Rommel, son of the great general. In Woody's recounting, he asked Rommel why his father had not pressed his advantage at Dunkirk and annihilated the British army. Rommel quoted his father as saying that with all the horrors of war he had witnessed and inflicted, he had a chance in Dunkirk to do "one good thing" in all the war. He took it.
The truth? Self-serving bullshit? The ramblings of a coot? You be the judge.