Francesco Quario’s review published on Letterboxd:
I have read many comments about the film's loud, overbearing soundtrack, and having somewhat recently rewatched Inception (as well as having seen Dunkirk in the cinema) I thought I knew what I was getting into. But it's much, much worse than I thought, and let me stress this: if you have sensitive ears or are susceptible to loud noises, do not watch this film in the cinema. There were several points during the screening when I was in physical pain and I had to cover my ears, and I never have these issues. It's not about the dialogue being inaudible, it's about the danger of your eardrums bursting, which (if the theatre takes the proper precautions) is probably higher than that of catching COVID-19.
With that out of the way, let me talk about the actual narrative. There was a point during the film when I was thoroughly enjoying myself: about halfway through, Nolan fully embraces the zaniness of the central conceit and uses it for a quickfire series of cool action shots and role-reversals, as The Protagonist travels backwards through time and encounters himself travelling forward. Unfortunately, that equates to a 20-minutes stretch in an 2 1/2-hours long film, which is otherwise a bag of dull, pretentious crap.
A film like this cannot (I repeat cannot) take itself too seriously. I wouldn't make the same argument about Inception or Interstellar because, as inherently whimsical as those films are, their gimmicks have somewhat of a scientific or theoretical backbone. The central gimmick in Tenet is the idea that time is on a line, and there is a technology which allows objects and people to move backwards on that line. Explained in these terms, it's as simple as it gets with Nolan, and yet the film manages to make it unnecessarily complicated. The reason being that this conceit makes no sense based on everything we know (both scientifically and philosophically) about time, and its sole purpose is to craft some cool-looking action shots. Which, as I stated earlier, are only effective in about 13% of the film's runtime.
What would Nolan do with such a conceit for the remaining 2+ hours, instead of using it for cool action shots? Nothing. He crafts an unnecessarily cheesy, overstuffed narrative, with two central characters (Washington and Pattinson) who only exist as deliverers of one-liners and two side characters (Debicki and Branagh) whose dynamic is genuinely interesting but completely unnecessary to the central purpose of the film.
And the one-liners are... well, let's just quote "This is the end of a beautiful friendship" and leave it at that.
Verdict: not worth bursting your eardrums for.