When Holden first sits on the floor as Brian is playing with the Lincoln Log toys, Brian can be seen putting the red roof pieces onto the stack of logs. In the next scene as the camera shows the full room view, Brian is still stacking logs on the tower and the roof pieces are on the floor in front of him.
In the end credits, the Boomtown Rats' "I Don't Like Mondays" song is playing. This song wasn't released until 1979.