Revealing mistake: When the doctors first arrive by helicopter in the town, they're looking around. The Minister lying upside down on the stairs moves his eyes and forehead as if looking to see what's going on, on the set. (00:22:15)
Revealing mistake: When Dutton, Hall, and Stone are undergoing the first level of decontamination, they walk into the treatment area while completely nude. When the distorted shapes of their bodies are seen on a thermal imaging screen, you can tell that Hall is wearing briefs, even though they are supposed to have no clothing on whatsoever during the decontamination process.
Revealing mistake: During the helicopter flyover several 'corpses' are seen lying in a depression in the dust where they fell after dying (imagine a 'snow angel' to see what I mean). However, there are no footprints leading up to any of them. Any soil loose and powdery enough to form a depression when a body lands in it would hold footprints. And if there was a strong enough wind to erase footprints it would have piled some of the dust up against one or more sides of the body.
Suggested correction: Unless you are suggesting that the production crew dropped the actors into place from a helicopter, the configuration you see is obviously possible in real life. The actors playing the corpses walked to their positions for filming.
Or more dust was laid down by the production crew once the actors were in place, presumably to cover the crew tracks which would have shown a lot of activity, and had the side effect of covering the actors' prints too. They either didn't realise or didn't think it was worth recreating the steps.
Revealing mistake: When Hall and Stone are looking into the windows at Piedmont, they see an old man lying dead in a barber's chair. When the camera switches to a reverse angle of the man's face in close-up (looking back out towards the window), the man's bottom lip is moving.
Revealing mistake: When the monkey is on the autopsy table and the screen is split between the rat and the monkey, the fingers on the monkey's right hand flex twice. Of course the monkey is an actor and not really dead but he's supposed to be dead in the movie. (01:16:55)