Kyle Bruce’s review published on Letterboxd:
Tenet is the first Nolan film I've had real trouble keeping up with. As the first hour of the film goes by you start to think you're getting your head around the time 'inversion' concept, and you think you know the general plot of the film so far. However, when these two things collide, and we approach the big final act, the film doesn't slow down at all to let you comprehend what the f*ck is going on, and there's some key exposition that's very easily missed.
Meanwhile, Washington, Debicki, Pattinson and Branagh are all great as usual, and the (mostly) practical effects give the film a very authentic feel.
Suddenly, you find yourself at the end of the film, everything comes together in a very Interstellar way, and you can appreciate Nolan's genius, but it still feels like you missed something. It does leave something to be desired but, just like the film, you can't quite figure out what...
Essentially it's like watching Memento and Inception at the same time.