Sonny Bunch’s review published on Letterboxd:
So, the movie is centered around a gimmick designed to immerse you in the film: it is, supposedly, one long continuous shot (broken at one point when the lead actor is knocked unconscious). But, obviously, it's not a single shot; they didn't do this in one (or two) takes. Which means that the discerning viewer spends most of his time looking for the seams, for the moments when camera movements obscure a cut. Which means that the gimmick designed to immerse viewers in the harrowing experience of life as a WWI soldier has the literal opposite effect.
That's obviously a problem. Interesting idea, solid execution, but fatally flawed for reasons that the filmmaker can't really help.
THAT SAID: It's entertaining enough and Deakins does some really fine work, especially later in the movie during a nighttime fight lit by flares. Soft-recommend.