First a brief discussion of the theater-going experience; in my state there are (wisely) no theaters open so we had to go south to Toledo; we entered a cavernous, yet bland one floor mall from the opposite end and there were several hundred people in the mall with varying degrees of social distance practicing; however when we reached the theater there was no one in it and it gradually filled to a staggering fifteen viewers. This was more or less as predicted, Tenet (so far) has made $30 million domestically and in a non Covid world would have made somewhere around $200m by this point (and ~300-350m lifetime, an additional 400m or so worldwide) so had to anticipate a small audience. That said they appeared to all be stalwart movie-goers and no irritation was had throughout.
Tenet is an extremely ambitious film; picking up from Inception Nolan was not dissuaded by criticisms of how much exposition he could use so he made this entire movie nothing but exposition. That said the dialogue and performances in Inception work pretty well and the main emotional components happen in brief sudden instances, but those in Tenet are drawn out for half hour long segments with minimal resonance. The actors are fine, I suppose a bit lower tier than the usual Nolan casting extravaganza; each of them has had strong performances in the past but Nolan dialogue is a different monster than what they were used to. Even an established Shakespearean actor can have troubles parsing inscrutable dialogue.
Christopher Nolan is not here for dialogue, he's here for interesting philosophical and partially scientific concepts expressed through creative film-making. The final bit of exposition is basically yelling "DETERMINISM!" emphatically at you. If you're not familiar determinism is the idea that every action taken is based on every choice you've made in your life prior to that moment; it is an invincible argument logically and of course contravenes every notion of free will that you have. It does not preclude the perception of free will by participants merely the actual existence of free will itself. Determinism is extremely compatible with monotheism though strangely rarely emphasized by theologians, perhaps because it is difficult to understand for the layman.
A mild spoiler warning here, I won't necessarily discuss specific elements of the film but I must discuss the primary element dictating object time travel. There are vaults in the world of Tenet where entering one side reverses your position in time so that you travel in reverse; this is very well established by the hour+ of setup for it, much like Inception (but not as elegant); and then you have a long sequence that slowly demonstrates what happens to the reverse travelling person. In Tenet there are at least two "loops" but you can infer that there are more happening behind the scenes *somewhere;* however they are all happening within the same time continuum.
The idea here is that they're trying to avoid the multiple timeline fallacy (even discussed as the Grandfather paradox in the film), but since every different version of yourself that's been through the vault exists in the world simultaneously eventually the whole world would be populated in an inevitable infinite timeline scenario; so there are actually infinite John David Washingtons, Elizabeth Debickis, Kenneth Branaghs, and Robert Pattinsons amongst us somehow magically avoiding each other; that's right an entire world filled with 6'3 anorexic women. This is a Nietzsche sentiment that is one of the better ways to express Determinism logically as well as the still tenuous primordial soup theory, but I haven't seen it in a single timeline before so that's neat if completely impossible to portray on film.
Hence the ambition, so in the limited scope of the film there are three such internal timelines within the timeline and what's really interesting is how they film it all from different perspectives. There is some CGI to be sure but I think they did actually shoot like 150 soldiers running different directions from a dozen different camera angles and somehow make it coherent. There's no Dark Knight truck flipping or Mad Max: Fury Road final car chase but the very concept of how the action scenes proceed is incredibly impressive.
The score is actually not by Hans Zimmer for once, it's Ludwig Goransson of Black Panther, Creed, and The Mandalorian fame; like seemingly every Nolan movie ever it is utterly fantastic especially in the action sequences. I guess you wouldn't listen to it by itself like you might Tron: Legacy or Ennio Morricone but man does it work well in a movie theater. Maybe Nolan is just trying to expand who he works with since there's only a handful of token "Must appear in every Nolan movie" appearances, but I assume someone like Guy Pearce could have carried the questionable dialogue and lack of viciousness; alternatively you could have made the movie R rated. In (the comically ludicrous) Lucy there is an extremely violent scene with the prime heroine of modern heroines (Scarlett Johansson, the weakest part of the Prestige) being kicked in the stomach; in this movie there's that scene except nothing is shown and the cuts don't make much sense, the villain establishing scene which utterly fails to establish the villain.
Nonetheless I still find Tenet to be a bit more philosophically compelling than Interstellar; Interstellar is unquestionably more emotional which perhaps Nolan has difficulty expressing in real life so that might be a personal accomplishment for him; but the exceedingly grounded scientific elements of Interstellar are not as interesting as the more philosophical elements in Tenet (though I'm sure it makes more sense than virtually every other time travel movie ever). For me that matters more since I'm not going into a Nolan movie to tug at my heartstrings but moreso to have a conversation with an intellectual peer and a dear old friend.
Aside: It's interesting that the film industry is pushing out quite a few movies in a short time period from now till whenever COVID ends, worldwide the movies are doing quite well, like 70% of their expected gross; enough to cover the cost at least. But domestically they are doing horribly; even something that looks incredible like WW: 1984 is probably going to gross under $100 million domestically; I think there's just too many of these movies out to re-release them all later; so at most like five will be released again in 2022 or whatever and all the rest will rot in this increasingly odd timeline.