Tenet ★★★★½

1st watch: 3.5*
⬆️ Unsurprisingly, given that this is a film designed for repeat viewings

The most important thing to understand is that the film is not about time travel, but the more specific concept of time inversion, where a character or object can move through time in reverse, but at the same speed.

This creates an opportunity for Nolan to pack 2 scenes into the one we usually see.

I think the creators will especially empathise the creative drive to do this. When you work on a piece, you live it multiple times, and to keep yourself interested you want to pack as many meanings into it.
Consider my song "Island"  on smalltown dreamer LP (a-side).
I had written the first half, (eg "me and a girl") then I read about The Tempest and realised I could through wordplay make the 2nd time round (e.g.  "Miranda, girl") also be about The Tempest.
Listeners who get it get closer to the deeper experience song creation.
It won't really affect a general listener: they might be like "why is he mispronouncing his words slightly?".
And that is the art: balancing creating a 2nd deeper layer, while not compromising your base layer for the normies to enjoy.
Tenet is the most ambitious attempt I've ever seen to push on the 2nd layer. A movie is uniquely well-placed to do so because of the bread and circuses (action scenes, Bond tropes, RPatz's face) Nolan can throw to keep the unwitting appeased.

And boy does he keep them unwitting: 
He removed a lot of the original script's exposition that MIGHT allow a 1st watcher to grasp it. I think he gave up on bringing everyone along, and just decided: "hey, some people will just enjoy the first half as a Bond movie and then probably leave hating it. I don't care".

Nolan's more interested in tricks like this:
That listener-unfriendly 'industrial techno' I heard first-time round: yeah that's actually 'palindromic music'
The obscure names like Arepo and Opera: yeah those are part of an obscure palindrome called the Sator Square

He did some confusing things, which didn't add any higher-order value:
muted some key dialogue, leading some to believe he is actively making it difficult for 1st timers to understand
- Having 2 scenes (opera and halide gas in freeport) in which forward-movers wear masks, which obscured the mask as a clear identifier of backwards-moving
- the first 8 minutes opera scene didn't actually really add much clarity. In my first review, I'd assume Jair with-held it from me because it would tie a loop together, but Neil's involvement was too subtle for me to be clear. I agree with Jair that the film would have been clearer if it had started from the first 'Tenet' title.

Ultimately though, VVarner Bros. cared that normies hated the second half and told their FB friends not to brave the Covid for it.
VVB decided that they can't bank on the Nolans of the world to deliver cinema-efficient popularity levels, and are just gonna stream through HBO Max.

Does this mark the end of 2-levelled (or arthouse  / complex ) entertainment. 'Artertainment' maybe?
I'll do my best to carry to the torch with my pop music Christopher.