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: When Marie goes to sit down by the fireplace to care for the Nutcracker, who just had his teeth broken by Fritz, the chair has purple cushioning. Moments later when she is about to get back up, the chair changes styles, and the cushioning is blue.