Nolan simply made an epic film about survival...

Rating: 8/10 (23 September 2017)

... and it worked! At least for me. Now for a few words about that Nolan style in this film.
Christopher Nolan wants to have his cake and eat it too, and he's been successful enough that he's one of the very few directors who gets the opportunity to do so anymore, in a franchise world where the auteur theory is dead and producers are way more important than directors (witness Kathleen Kennedy firing the Lord brothers from the Han Solo movie because they were actually attempting to impose a personal vision upon it, something the Star Wars franchise will never allow any director to do ever).
Nolan wants to work in super-mainstream genres: super-heroes, war, science fiction. But he wants his product also to be very self-consciously and in-your-face artistic. He sets up little rules for each movie and he plays by them, and it's up to the viewers to figure them out.
There are three main story lines in Dunkirk, and each one unspools over a different frame of time. So, the Harry Styles story line covers one week of time, the Mark Rylance story line covers one day, and the Tom Hardy story line covers only one hour! This information is provided to us at the beginning of the movie. There is a title card that reads "1. The Mole: One Week". This is supposed to tell us that this particular story line in the movie is going to cover one week. But I spent 15 seconds thinking, "One week? What does that mean?" before there was so much shooting I got caught up in the action on-screen and didn't think about the title card for the rest of the movie.
It wasn't until later that I was enlightened as to Nolan's intent. I am accustomed to movies tinkering with time concepts, yet I didn't get that this movie was playing around with time for the entirety of the time that I watched it. I was like, man, Tom Hardy has been in that plane for a really unrealistic amount of time! I'm just arrogant enough to think that if I didn't get the time tricks, then I'm guessing most of the viewers of Dunkirk didn't get, or didn't even notice, all this jumping around in time. Doesn't really distract from one's enjoyment of the movie, unless you stop to think about Tom Hardy still being in that plane ...
Other extremely self-consciously artistic Nolan choices: no German soldier's face is ever seen clearly in the entire movie. Also, the violence is very self-consciously bloodless and sanitary. Nolan has said he wanted the movie to be about rescue and heroism; not war and violence.
There's also a ticking stopwatch motif playing on the soundtrack virtually the entire movie. Nolan's call or Hans Zimmer's, I don't know. The stopwatch features very prominently in the trailers, but I didn't know it was also going to run for the duration of the movie, as well.
If everything I have written seems like I didn't like the film, let me say that is not true. I get that Nolan could have made a conventional war movie, but he took a home run swing and went with something much more experimental, and I thought his reasoning for this was pretty clear by the end: this is NOT a classic "hero's plot arc" story. It just doesn't fit that mold. You could see in the conclusion that most of the fighters felt like cowards and failures. To paraphrase Churchill, you don't win wars by retreating. And, yet, there was a humble, understated glory in this moment. This was a movie about duty above all else - just many small people doing the small things asked of them.