Continuity mistake: In the scene where Joe Gideon is helping his daughter with dance exercises and realises that it is time to put Michelle in a cab, he carries her out of the rehearsal studio with her facing forward and her legs wrapped around his back. They turn a corner to go outside and she magically is facing him arms around his neck and legs wrapped the other way around his waist. Also Michelle suddenly grows a yellow rain jacket. There is no time lapse in the dialog which would explain this turn.
Deliberate mistake: After having wrestled with Santini in his office, Col. Virgil Hedgepath tells Santini, "And no more assaulting corporals in the latrine." Marines use the naval term "head" in refering to the restroom, and would never call it "the latrine." However, since "latrine" is better known to civilians, this could be a deliberate mistake by the film makers.
Factual error: Throughout the film the British infantry are armed with carbines. These were intended for issue to cavalry and are much shorter than the infantry issue Martini-Henry rifle.
Plot hole: When Jack The Ripper checks his watch before confronting H.G. Wells and demanding the key, the hands point to 8:50, the ensuing chase to the museum and demise of the Ripper may have used up a half hour or so, yet the time on the wall clock indicates that it is midnight.
Visible crew/equipment: Young vampire Danny floats away from the window after being confronted with a crucifix. The effect is quickly ruined when the boom he is sitting on can be seen moving him for 8 seconds. (01:43:40)
Plot hole: In one scene saboteurs rig the Concorde's cargo door to automatically open suddenly in flight, on the principle that the rapid decompression will cripple the airplane & cause it to crash. At the critical time the door does start to open, but jams and only opens very slightly. Minutes go by, with the ajar hatch allowing air to freely pass through. Then, suddenly, the door unjams, and the compartment is shown losing air pressure dangerously fast. Problem is, that since the door had been cracked open for several minutes, the air pressure would surely have gotten to equilibrium by that time. (01:32:45 - 01:36:30)