Audio problem: In the shot where the kids are locked in the police car, banging on the windows yelling at the policemen, their cries are muffled as if the car was totally closed up. As the camera zooms in, you can see the front driver's side window is open so the kids' voices should be much clearer.
Continuity mistake: When DJ, Chowder, and Jenny are drawing the dummy with the cold medicine, before DJ walks in there is nothing next to the Nebbercracker house drawing except two trees. But, when DJ comes in, there is a dotted line going to the house, a drawing of the kids in a circle, and a drawing of a red eye in the doorway of the house.
Continuity mistake: When they go to ding dong ditch the House, there is a tree stump in the yard. When they leave and are up in their room spying, the stump is gone and it's there again when they go back. This continues throughout the movie.
Continuity mistake: Jenny rings the doorbell and Zee answers it. However, in some far shots you can see there is no doorbell.