Deliberate mistake: In the Spanish release, the name of the family store is written in Spanish, but inside the place it's in English everywhere. This is a very common mistake in foreign kids' films released in Spain.
Continuity mistake: The appearance of Grace's house by the front door (to the left of the screen) changes from the time Billy is standing along the road to when he meets his mother half-way. At first, the side of the house is mostly white; it is mostly brown thereafter. The garage area to Billy's left also changes color from brown to white. (00:05:22)
Continuity mistake: Monica's station wagon and the moving van Jacob drove to their new property in Arkansas are not parked in the same positions moments after their arrival. Initially, both vehicles are at some distance from the mobile home (or trailer) and are roughly parallel. When the camera shifts to a view from the vehicles toward the mobile home, the vehicles are suddenly a lot closer and their front ends are angled toward each other. (00:02:13)
Continuity mistake: There are some continuity problems during the cafeteria scene where Fern is being introduced to her co-workers. Fern is holding a banana, peeled almost to the bottom, and has several slices of banana on her peanut butter sandwich. There is another banana peel on her paper lunch bag. Fern is shown taking a bite of her sandwich. A little later, Fern is holding a partially peeled banana but no slices can be seen on her sandwich. If this is her second sandwich, she already peeled two bananas. (00:05:59 - 00:06:32)
Continuity mistake: The amount/shape/size of the blood/cut on the bridge of Joey's nose varies, as does the obvious presence or absence of blood on the right side of his nose. (00:42:32 - 00:43:50)
Other mistake: "Sally" the Great White Shark rammed Emma into a rock (or other hard object) underwater and Emma only got a small cut above her right elbow. It isn't clear how fast Sally was swimming, but Emma was rammed with force (and appeared to hit her back). A female Great White Shark weighs about 4,000 or 5,000 pounds, so Emma would be expected to suffer a major (not minor) injury under the circumstances. (00:05:24)