I acknowledge I might have had a very different experience seeing this in a proper IMAX theater. But at home, it was a bit underwhelming. (I saw Interstellar at home, though, and was blown away, so who's to say?)
Having read a little about the actual Dunkirk, I was disappointed by how small-scale this movie was — a few hundred soldiers on the beach, two allied planes, a couple dozen citizen rescue ships. I respect the choice to focus on a handful of characters, that's necessary and fine, but this bears no resemblance to the magnitude of the Battle of Dunkirk or the escape.
(SPOILERS)
I don't understand the choice to make this a bloodless war film. Bombs fall and create limp bodies but no carnage. Bullets hit people, but we aren't shown what happened. This is weirdly not as horrifying as it should be. Seeing the ships sink so quickly was horrifying, I'll give you that. But all the death was strangely muted. This feels more like an adventure story. And nearly all the protagonists survive. Considering that
11,000 British soldiers died because they were not able to escape, none of that feels quite right.
The chronological shuffling was good. That actually worked. Things were not too hard to follow. People who are calling this an experimental film are out of their minds, though.