Revealing mistake: Throughout the film, the base station radio is not connected to an antenna. In many lengthy shots of the back of the radio we can see the power cord trailing out the back of the unit, but there is nothing plugged in to the antenna socket. This is especially annoying because base station radio problems are a key plot point.
Revealing mistake: The person slamming Blaire's laptop shut at the end is a male crew member.
Revealing mistake: At the end when April and Kyle are killed, they are thrown in a hole back first. When they are shown, they are neatly positioned beside each other. April even has her knees bent up and Kyle has his arm around her waist meaning they obviously positioned themselves for the final shot.
Revealing mistake: When the girl gets her head cut off with the barbed wire, when her body falls to the ground, her feet bounce around like rubber.
Revealing mistake: At the end of the movie, it's pouring rain but the 2 survivors aren't getting wet at all.
Revealing mistake: Tortured by the demonic voices in his head, Michael King goes into a self-mutilating frenzy with a kitchen knife, except that he squeezes the handle of the bleeding-knife prop a bit too hard and it squirts fake blood horizontally across his chest.
Revealing mistake: When the woman is tied to the bed, she is holding the ropes, and the rope isn't tight on her right hand; she can easily escape. (00:20:10)
Revealing mistake: As Glenn, Blake and Monica are being surrounded by zombies, as Monica asks "Fucking hell, how many more of these are there?", in the background you can see a zombie sitting astride his victim, flailing away with a hammer or hatchet. It is obvious that he is just swinging his arm back and forth, without connecting with anything. It looks as if he is dusting, not slaying someone. (01:23:50)
Revealing mistake: In the scene were Viago is showing the locket that his girlfriend, Katherine, gave him, he puts it on, and since it's silver, it starts to burn his skin. The smoke from his burning flesh is coming from something on the table in front of him, not from inside his shirt.
Revealing mistake: When the stewardess asks April to sign her copy of the book entitled "How to Survive a Sharknado and Other Unnatural Disasters..." it's a thin book, and in the closeup as April autographs the page we can read the text and it's actually one of the versions of the "Samsung Galaxy Tab...For Dummies" book, not April's book. Also notice when Kelly Ripa shows April's book to the audience, it's now at least 4x as thick.
Revealing mistake: When Millie is being carried away, her head remains completely upright as though under her own control. If she was dead her head would hang back.