Debbie's panties change from blue to white, back to blue and then white again before she goes into the tub.
At about 24:50, Debbie has bath soap on her as she runs down the stairs. A moment after the camera moves to Billy and back to Debbie, the soap suds are gone and her skin is dry. As she then hides behind Billy, is being chased around the table and eventually falls down, her skin is wet and the soap suds return in varying amounts.
At about 18:34, there is a box of Froot Loops on the breakfast table. Later in the scene, it's gone.
The day after they move into the house, Debbie says she's only had 15 minutes of sleep all night and can't face starting school on that amount of sleep. Later, Billy mentions starting school on Monday (within the same day).
When Debbies gets in the tub she props her leg over the rim. In the next shot her legs are both underwater.
Zipper seen on back of the head of Creature from the Black Lagoon.