Overall

Genuinely I thought it was a great film. Technical and cinematic masterpiece using very little CGI and using real ships, planes and actual locations where the famous Operation "Dynamo" happened. It's true that the characterization is shallow but Nolan himself said that is all about this battle and the situation these soldier found themselves and he tried to make you feel like you were there with them rather than focusing more deeply on a character development. It is certainly a different approach than the other WW2 films, for example Saving Private Ryan or more recently Hacksaw Ridge, where you could connect with a character on a emotional level.