I have never seen anything on screen like this before. Cinematic genius!

Rating: 10/10 (11 January 2020)

I just came back from seeing '1917', and it's a tense, absorbing, grim, and yet inspiring 2-hour journey. The theater was packed, and you could sense that every single person in the audience was mentally and emotionally glued to the screen. It's a fictional story, but built from real elements that director Sam Mendes heard from his grandfather, who acted as a messenger during WWI in just the same way as shown in the film. The WWI setting and the basic storyline sound familiar enough, but it's all in how the pieces are put together, and having seen it I now know why it's a Best Movie of the Year contender.
A bit more than halfway through the movie there is an absolutely riveting centerpiece: a few British and German soldiers are trying to get through a ruined French town at night without being spotted and killed by the other side. Half-fallen buildings and corridors of stone arches are illuminated by flickering light from bombs and flares that come and go while they hide and run. It's as if we've stepped into an eerie, lurid half-world from a fever dream. I've never seen anything like this before, and words don't do do it justice -- just go and see it. This scene when added to several others feel like a tour through the circles of Hell (as in, Dante). That sequence is almost equalled toward the end when, the next morning, the battalion goes 'over the top' from the trenches while one of the messengers, Will (played by young George MacKay) runs desperately down the line across them to deliver the crucial letter (a small part of that scene appeared in the trailer but the full scene packs a far bigger punch).
Aside from the big set pieces, the whole film is beautifully constructed, seems to flow organically from beginning to end. Like the ads say, it feels like "one long take" (which it really isn't, but it goes further with that technique than any other film I know of). What that does do, however, is make the action relentlessly personal and individual with the focus on the two messengers, Tom and Will. The two lead actors MacKay and Dean-Charles Chapman nail it as two ordinary soldiers asked to do things that no human should have to experience. They are not superheros: the real heroism, for them, is simply surviving and persisting through their own fear and confusion, long enough to get their job done. Bigger names like Colin Firth, Mark Strong, Benedict Cumberbatch, Richard Madden, and Andrew Scott fill roles that are essentially big cameos, but they importantly bookend the story.
And I also want to mention Thomas Newman's musical score. It's superb. It's unobtrusive (or silent) when it needs to be, and epic when it needs to be: it emphasizes what's going on without taking over.
100 years after the actual events, I don't know if it's possible to get any closer than this to recovering the lived experience of World War I from the viewpoint of the individual soldiers. A great companion piece to "1917" would be Peter Jackson's documentary "They Shall Not Grow Old" (2018) built from recovered and restored film footage taken during the actual war. It's brilliant too, but in a different way. But it verifies that "1917" almost uncannily hits the right notes. WWI can never be portrayed as anything other than horrific, but (maybe for that reason) it's been a magnet for lots of past movies good and bad. Some other recent films that use WWI very effectively though much more briefly in their storylines are "Passchendaele" (2008, Canadian-made), "Tolkien" (2018), and (yes) "Wonder Woman" (2017). But "1917" goes past them all.