Deliberate mistake: When they get the beach to surf the windows in the truck are left open, but after the shark attack Byron comes running back to call 911. The windows are now closed, so he has to throw the rock at the window and get the cell phone.
Continuity mistake: When the whole family is in the kitchen on the day that Bethany comes home from the hospital, mom asks who wants sandwiches. Bethany tries to cut the tomato but it falls on the floor so mom picks it up and starts to cut it. When the camera is zoomed out, mom makes the first cut of the tomato, when the camera zooms back in on mom cutting the tomato, she makes the first cut again.