When Katherine and Ben are wading through the river of blood, Ben stumbles and the left sleeve of his shirt and his bag dip into the river and become visibly wet. A short time later, when frogs start raining from the sky, both his shirt and the bag are completely dry. Even if there were time for the shirt to dry, the blood in the river would inevitably leave a stain.
When Katherine talks to the boy at the cattle farm, he is drawing with crayons. In the "over his shoulder" shots he is using a green crayon. In the "across the table from him" shots, he is using a blue crayon.
When Kathrine walks up in the girl's house for the first time she has a smaller circular barrette in the back of her hair. A short time later the barrette suddenly changes to a much larger rectangular one.
The young boy colors in some yellow in the lower left corner of his drawing showing the young girl and the dead cattle (adding to a little yellow already present). But when the female miracle debunker pulls out the drawing later, it had only the tiniest hint of yellow.
Katherine's missing bracelet appears on her wrist when she goes inside Lorens house, despite being lost at the dam.
The city shown as "Concepción, Chile," at the beginning of the movie is nothing like the real location. Concepción is located along a river (the Bíobío), not a sea, and has a cold and rainy climate, many modern buildings (especially in the city center, where the cathedral is located), and no heavy industry. Additionally, the Chilean police uniform is dark green, with long jackets and boots and no beret, and Chilean police and Armed Forces personnel are not allowed to wear beards, only mustaches with superior officer approval.
In the slide show presentation in the beginning of the film, there is a slide show displaying both methanol and ethanol. However, the molecular structure labeled as ethanol is in fact methanol, and methanol is labeled as ethanol. Also, the structures displayed for both other chemicals on the same slide, DMSO and benzene, are incorrect.
At the beginning of the film, when they claim to be in Concepción, Chile, the accent used by the city's population is clearly Central American, not Chilean.
Isabelle says that her husband just bought a Ski-Doo and hadn't even got it wet. A Ski-Doo is a snowmobile. She should have referred to the watercraft as a Sea-Doo.
Katherine and Ben are talking on their phones in the bayou when Ben tells her to come to him. She said she wasn't far but how would she have known since locations for either of them were not mentioned.
Towards the end of the film during the second flash of lightning, for just an instant in the upper right hand corner of the screen you can see a serial number.
At the end of the film, as Katherine emerges from the crypt and sees a white egret flying overhead, the sound is that of a hunting cry of a bird of prey, perhaps a peregrine falcon.
When Loren grabs her mother from behind 1:02:03 Loren can be heard screaming and yet her mouth is not opened. Her teeth are clenched shut.
When Katherine is giving Ben her list of causes for the 10 plagues, she states that locusts would have been blown into Cairo. The plagues took place around 1400BC, but Cairo didn't exist until 969AD, and didn't become the capital until 1168-1169AD. She should have used Thebes as the reference city since it did exist then, and was Egypt's capital.
Katherine refers to the country of Sudan as "The Sudan." Since she is a missionary and a professor at a major university, it is unlikely that she would make that mistake.
When they are leaving the church/school, Ben tells David that lice are the fifth plague (and holds up as many fingers). Gnats/Lice are actually the third plague as told in Exodus.
Upon first arriving in Haven, Katherine and Ben drive past a large red brick building and then immediately blow right through a stop sign (which has a police car behind it on the cross street).