Best sci-fi movie mistakes of 1979
Continuity mistake: In the shot of the alien's tail wrapping around the back of Lambert's legs right before it kills her, the floor is different to what it was before, there is water suddenly falling from the ceiling when there wasn't before and her trousers have changed from white to blue. This is because that shot was originally intended to be used when Brett was killed.
Continuity mistake: In the final scene on the bridge, Spock and McCoy are wearing colored arm bands which identify their departments: Spock's is orange (for Science) and McCoy's is green (for Medical). In the very last shot, Spock is wearing the green band and McCoy is wearing the orange one.
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.
Factual error: In the PALOMINO scenes, Anthony Perkins wears a long lab coat. In most of the scenes, it hangs straight down; but in the low gravity aboard the ship it should be flattering about (that's why such loose garments are not worn by real-life cosmonauts; they would be a hindrance).
Factual error: When Mission Control talks with Challenger 2, the Spacecraft's camera feeds of the Crew are displayed up on two wall-sized TV screens. Between them is the familiar Mercator map of Earth with the ground track of a low-orbiting satellite superimposed. Challenger is nowhere near low orbit: it's out past Mars, in the Asteroid Belt. The middle screen would have a schematic of the ship's interplanetary path.