Other mistake: When the Ashleys are first shown playing jacks, Ashley T's nose seems to be missing; then it reappears three shots later.
Other mistake: After Dave takes away Mikey's lunch tray, it fades to a shot of the school clock, and there is no 5 on it.
Continuity mistake: After getting off the school bus, when Gus falls into the hole that Sam has dug in front of the school, he's wearing his watch as usual. As Gus sits up, his watch vanishes mid-shot; then it reappears on his wrist.
Continuity mistake: After Upside-Down Girl tells TJ he must do something about Dave, when the gang look for Sam and discuss the situation with him, the clock over the school doors repeatedly changes time between shots. Then, when Sam grabs the shovel and jumps back into the hole, the two hands of the clock vanish, only to reappear and change time yet again.
Other mistake: At lunch, when Sam is using a spoon to shape his mashed potatoes on the tray, his right arm clips through the tray just as he says, "Maybe I should clear out the east wall like this." Then, when Sam says, "Maybe I should fortify the south side first," he's using the spoon to move the mashed potatoes on top of the tray, but his arm and spoon are under the tray, so it looks as if the potatoes move on their own. Additionally, when Sam states that he's so confused, the spoon held up in his right hand appears to vanish in the next shot.
Continuity mistake: The gang hatches a plan and tells Dave that Sam is trapped in a cave-in, so Dave begins digging to save him. When Sam and Spinelli return with their ice cream cones, Sam's gloves vanish and reappear a couple of times while he is holding his ice cream.
Other mistake: When the Ashleys are playing jacks, Ashley B is wearing her usual yellow sweater, but in the next shot, it becomes red, the wrong colour. It goes back to yellow in the next shot.
Continuity mistake: After it is explained that without Dave, Sam is unfocused, you see that he has dug holes just about everywhere. However, after that scene, all the holes disappear.
Factual error: After Digger Dave and Digger Sam split up, they show that Sam was unfocused and was digging everywhere. Even through concrete?