This the part of the movie where Henry (Macaulay Culkin) is sword fighting with himself on the porch. When he pretend stabs the air, he sticks his foot on the banister. If you notice his shoes are of a different color. One is black and the other is white. They stay the same way like that through out the whole movie.

Another slip up is when Henry's parents leave the kids at home to go out. Henry decides to play hide and seek and turns off all the electricity to the house. If you notice carefully when Mark (Elijah Wood) is running around the house looking for Henry's sister. He passes a room, and in the back ground the clock is still on.