Continuity: H.G. Wells' hand and spoon during lunch in the revolving restaurant.
Continuity: The number of framed photographs on Lt. Mitchell's desk changes from one to two, and back again, several times.
Continuity: During his interrogation of Wells, Lt. Mitchell throws the newspaper down on the desk, but in the next shot it's back in his hand.
Continuity: The cab goes up and down California Street and Nob Hill twice.
Continuity: When H.G. is reading about the fourth killing, the newspaper changes from being folded to unfolded and back again between shots.
Continuity: During the time travel sequence, the voice-over from King Edward VIII's (Duke of Windsor) abdication speech precedes Franklin Delano Roosevelt's "Fear itself" speech. Franklin Delano Roosevelt's speech actually came first, at his 1933 inauguration, while King Edward VIII (Duke of Windsor) abdicated in 1936.
Continuity: Mrs. Turner is standing on the stairs one step from the bottom, but in the next shot she steps down twice to reach the bottom.(00:19:46 elapse time)
Revealing mistakes: Just before Wells slaps Stevenson and shouts "Stop it!" Stevenson flinches noticeably in anticipation.
Audio/visual unsynchronized: During the scene where H.G. is in McDonald's and sits down to eat the food he comments: "Pomme frites...fries are pomme frites." However, it is clear McDowell says the British term "chips" which is later dubbed to "fries" in post production.
Errors made by characters (possibly deliberate errors by the filmmakers): In the early part of the movie in Wells home in the 19th century the chess board is set up wrongly. The black corner square must be on the left as each player faces the board.
Revealing mistakes: When Jack/John takes off H.G.'s Glasses before hitting him, the camera focus is thrown to show how poor H.G.'s vision is. Although Jack/John's face is badly out of focus the wall and door behind him comes into sharp focus, displaying an error by the focus puller - everything should be out of focus for this camera effect to work properly.
Audio/visual unsynchronized: When Wells names the "Scottish restaurant" at which he had breakfast, he says "McDonald's" but the line is badly dubbed over with "MacDougall's," which spoils the joke.
Continuity: The spoonful of ice cream Wells is holding in the restaurant goes from fresh and frozen to melted and dripping as the camera angle changes.
Crew or equipment visible: Wells drove up onto the Museum's steps. The reverse angle shot revealed the sandbags that made driving onto the steps easier while protecting the steps from damage.