One of my big gripes with the film Oppenheimer was the blast itself, obviously a climactic moment in the film.

It looked like someone set off a bunch of chemical explosives. That’s not how it looked in real life. Totally bizarre decision. I don’t know if they were trying to avoid effects on purpose of go gritty and retro or something but the “unearthly cosmic horror” feel of the first a-bomb blast is important. It’s what led Oppenheimer to recite “I am become death, destroyer of worlds.”

Because that's exactly what it was. I agree with you, the puritanism around special effects doesn't make sense when there's plenty of high quality archival footage out there, and instead of using that or CGI to look similar, you do something that looks completely wrong.

I felt the same, my thinking at the time was they didn’t want the bomb to steal the show. The movie was about the man not the machine.

/hah very articulate of me for this early in the morning

I'm never watching this movie again. The dead silence to 100dB boom was unreasonable, dangerous, and amateurish filmmaking. And not the least of which Atomic bombs aren't that loud.

Yeah, Nolan's well known for practical effects - to the extent of actually driving a 747 into a warehouse! - but this is one spot where that approach failed hard.

I’m of a similar opinion, Lynch created a better depiction of it in twin peaks season 3.

With the films budget they could have sourced a small nuclear bomb the size of the original Trinity test and detonated it just for the movie. Just make sure the camera is rolling as it's a one take shot.