Continuity mistake: When Ernie lifts the bike, he picks it up by the top wheel. When he is shown carrying the bike a second later, he is holding it by the lower bar.
Continuity mistake: When the monster puts down Hanso after she tries to escape, you can see her footwear is completely dirty, but in the next shot where the monster's tail uncoils itself from her body, you can now see the pink and white of her footwear that you couldn't see before.
Factual error: The guy who is invisible is ran down by a car while running after the cop and the scientist. He is shown getting up covered in blood. Everything about him is invisible which includes his blood. It shouldn't have been visible after the accident.
Continuity mistake: When the guy who swears way too much is pointing a flamethrower at the two other characters in the garage, he's holding the flamethrower nozzle in his right hand. But when he goes to roll up his left sleeve to show them his arm, he uses his right hand, and it's a direct sequence cut (note the left hand is visible in the same shot and is not holding the flamethrower). After he rolls his sleeve up, he's holding the flamethrower nozzle in his right hand again.
Other mistake: William B. Davis plays a US Air Force General. Unfortunately, the Wardrobe Dept took a CANADIAN Royal Air Force jacket and put US insignia on it. The noticeable difference is the epaulets, which don't reach all the way to the jacket collar. On US military uniforms, epaulets go all the way UNDER the collar.
Revealing mistake: The infant baby was computer animated in every scene in which the face appeared. Even the feet were obviously touched up by computer in the hallway scene. The lighting isn't quite right, the skin texture isn't quite right, and the child's face is just too animated.
Continuity mistake: When Joe meets the President he is wearing orange Crocs, but when the President grabs his head he is wearing black flip flops.
Factual error: Throughout the film, most Japanese words are spelled in Katakana. In real-life Japanese, however, Katakana is exclusively used for foreign words adopted into Japanese language, like 'table', 'television' (mostly it is abbreviated to 'telebi') and 'racing car'. But in the film, even indiginous Japanese words such as 'samurai' are spelled in Katakana, not - as they should be - in Hiragana (the syllable system used for native words).
Continuity mistake: After Stark fights with the Wakandians his armour is damaged, but while he is drinking on the ship the damage is repaired, then the suit is broken back again.
Continuity mistake: When Robert gets into the front passenger seat of the truck, the 90° bend in the road is a couple truck lengths away. The truck pulls out and can be heard driving away. When the truck is shown making the bend, it is a few times the distance away than it was. (00:05:18)