Continuity mistake: Glen Holland owns a Chevy Corvair throughout the film. The car at the beginning of the film is a 1961 model 500 (the base model with bench seats), but at the end of the film it is a 1964 Monza (the top of the line model, with bucket seats).
Continuity mistake: After the bell is rung, Marie and Fritz run over to where their gift from Godfather Drosselmeier is, still hidden under a veil by their parents. As they do, they rub past a table that is by the window, which is a considerable distance away from the Christmas tree by a few feet. But when Drosselmeier points out the Nutcracker hanging in the tree, the table is suddenly at most right up next to the tree.