Drew Edelstein’s review published on Letterboxd:
Even if this wasn't a 2.5 hour long movie that feels twice it's length, stuffed to the brim with endless exposition that serves as endless filler, the base premise would still be pointless. Time travel is most interesting as a form of wish fulfillment (i.e. Déjà Vu, the movie Nolan will always be trying to make), but there is no fantastical element to this, no emotional core to the concept being explored; it is flexing a network of plot elements for the sake of playing narrative jenga, building a wobbly tower of storytelling on a waterbed.
There is no chemistry in this cast and no charisma to this world. We see characters make sacrifices for each other but have no reason to believe they would, because to watch any exchange of dialogue between the leads here is like watching soggy cardboard cutouts brought to life. Every clumsy grasp at emotion is fumbled by how overcooked this whole thing is, an overdesigned machine whose gears grate against each other until all the mechanics collapse.
To be asked to stomach this faux-intelligence and tin heart is already an insult, but to be forced to stomach it in the way Nolan has designed it is even worse. The sound mix is abysmal (as many have already noted), but especially frustrating to me for being hard of hearing; picking out the signal from the noise can be frustrating even in the best of times, so to have key dialogue drowned out by the incessant bass boosting for the sake of some artificial and entirely nonsensical "intensity" is beyond insulting. It is insulting because Nolan has made incredible films I adore before, all of which have succeeded in large part because of their technical construction, using high concept ideas to convey a surprising amount of emotional depth. This is a pure regression in every level for him, formally and emotionally and creatively and technically. That it could fail so much while feeling as if it kicks me in the gut every time the bass peaks past 0 is so disheartening, because it is a sign that he is intentionally ignoring the most basic of standards to cultivate an identity that he had already firmly established.
There is no reward for navigating the mess of this film, the limp spaghetti structure of a plot bearing none of the genuine heart and insight that I loved from Nolan. There is only exclusion, confusion, and frustration, an avalanche of things happening all at once to do nothing more than overwhelm you.
That this was the film supposed to save theaters is beyond insulting, because that he would demand anyone risk their lives to see a movie at all, let alone one this fundamentally broken and pointless, is mind-boggling.
The hidden blessing to a year where the hype mills of the Hollywood system has been deflated is that I haven't been as suckered by the fervor surrounding such new releases. I'm not disappointed by Tenet because I was expecting greatness and because I was caught up in a hype cycle. I'm disappointed because it is flawed and unchecked in its pointless excess, as heartless a film in its content as it is in its distribution. I don't want to support Nolan if he is going to do his hardest to alienate me at every turn, and I most certainly don't want to support Hollywood if they want me to risk my life and the life of the entire theater industry over the success of such a colossal mess as this.