Tenet isn’t terribly difficult to explain, though it’s been too long since I’ve seen it for me to do it now. I remember watching it and being able to say, ok, it’s not airtight, but I know what Nolan was trying to do with the movie at least. It’s a very interesting idea, but while the execution has a normal amount of plot holes, they’re exacerbated by a story that uses what seem like plot holes as a story device.

It hurts our brains because effect is preceding cause, and because most sci-fi stories with time travel use it in the same way as they might use a space ship: to travel to a different place that has only tangential effects on the main location (even though they may make a big noise about the Butterfly Effect, in reality it’s rarely that severe) or to make nonsense shenanigans happen (things that have no basis in logic from any direction). Tenet actually did come up with a really interesting concept, and tried to give it interesting stakes, but got distracted by the shiny of “backwards bullets” and so let the logic suffer.