Continuity mistake: In one shot when the robbers are driving the bread truck, a door appears on the driver's side.
Continuity mistake: In the scene where the robbers were told to destroy all the evidence, they are throwing boxes of papers into a giant stove/inferno. When the scene begins you can see fire and smoke coming from the top of the pipe. A couple scenes later when the Newton family (who is following the vet) pulls up to the same factory, there is no fire or smoke coming out.
Continuity mistake: At the beginning when Beethoven was a puppy, the puppy switches are very noticeable. Especially when Beethoven is making his way to the Newtons' house, the colours of each puppy the film makers use for each scene are very easy to tell apart.
Revealing mistake: In the shot where Beethoven slobbers on the father's pants during the breakfast scene, you can see him pressing Beethoven's head against his pants, causing the "accident".
Factual error: The Newton children don't age at all between Beethoven coming to live with the family as a puppy and when he becomes an adult dog.
Continuity mistake: When the family is eating breakfast, Beethoven steals bacon off of a plate on the table. Before he steals it, there are 3 pieces of bacon, then the camera fades off of the bacon and then back on. There are only 2 pieces of bacon on the plate then.