Revealing mistake: When Lila wipes the cream off her face after Eddie gets the pill out of her nose, if you look at the towel, you can see a red mark appear on the towel. Most likely from the red make-up for her sunburn. (00:58:10)
Revealing mistake: During the long tracking shot at Dunkirk, steadicam operator Peter Robertson had a little assistance in getting around. This took the form of a kind of golf cart (from the beginning to just after shooting the horses), and later a rickshaw (from little after the choir to just before the steps ascending the billets). If you look at the ground to the left just as the camera begins backing away from the carousel, you can see tracks in the sand made by the rickshaw. Keep watching the sand near the actors' feet to see more.
Revealing mistake: When the boy accidentally shot himself, the gun wasn't pointed in the right direction at all.
Revealing mistake: When Chuck first moves into Larry's house and goes to sit down on the daughter's green chair, it's evident that Chuck's weight didn't collapse the chair but rather it's pulled out to the right as if it was yanked from under him to achieve the collapse effect.
Revealing mistake: When the dark-haired kid's hand gets cut off, no blood is ever seen spurting from the stump. (00:07:25)
Revealing mistake: When the Level 3 Sentry is firing up into the air for no apparent reason, it fires some rockets with a clear defined smoke trail behind them and disappear off screen. Then the shot jump cuts to further away and suddenly the smoke appears again, but the end of the smoke trails are solid and crisp indicating the animators used the smoke animation as if the rockets had just been fired from that spot... in the middle of the sky. (00:01:10)