Some stuff from the imdb page:
* Revealing mistakes: Before Corey pulls back the cloth from the bones, it moves a bit.
* Continuity: The pineapple and tray under Art's arm change positions between shots.
* Continuity: The car that Walter is taken home in has different license plates on the front and the back.
* Continuity: The Peterson's Jeep is missing its headrests as Ray and Carol talk while it is parked: they appear as they pull out of the driveway.
* Continuity: Once it has been thrown out of the truck, the garbage stays on the street for the entire film. However, it is gone at the end when the house blows up.
* Continuity: Carol shows up at the end of the film with a shorter haircut, on which Ray comments. However, in her last scene of the film, her hair is back to its original length.
* Continuity: In the interior shot of the car when Carol pulls up after the explosion the headrests are missing but an outside shot shows that they are back.
* Continuity: The bandage around Ray's head, after the explosion, moves up and down.
* Revealing mistakes: When the family is sitting down to breakfast, Art is in the backyard tracking some crow with his rifle. He fires several shots, that sound like a rifle, but it is really a Daisy pump action BB/pellet gun.
* Continuity: During and after the scene with the bees, you can see Walter in the background walking towards his door three times.
* Continuity: When the group hears the doctor's footsteps while in the Klopek's living room, Carol is seen in the background removing her left arm from a piece of covered furniture. However, the next solo shot of Carol shows her removing the same arm from the same furniture again.
* Crew or equipment visible: As Carol is leaving for the cottage a reflection can be seen in the car mirror of a man wearing shades.
* Errors in geography: The car Walter rides home in has Illinois plates but in one scene you can see mountains in the background. Also, before the credits they zoom out of a geographical map placing them near Des Moines, Iowa.
* Revealing mistakes: At the beginning of the movie, when the paper boy is riding down their street the camera gives a view of the street head on in which the street sign "Mayfield Pl." is shown; however the street sign is positioned such that it would be showing the cross street, not the street they live on.
* Revealing mistakes: When Art and Ray are in the basement talking about the incubus and succubus, Art accidentally hits the lamp causing it to swing back and forth. As the light begins to slow down, one of the crew members hits the lamp again to keep it swinging.
