When Liz Taylor breaks the oval mirror in her bedroom, she then lies on the bed with Rock Hudson and when she gets up, the mirror is unbroken for her to sit down and look into.
The flashback of Heather accepting Jason's daiquiri (as Cherry relates the tale to Miss Marple) omits her saying she's never tried one before.
When Lola Brewster us changing in front of the Inspector in her dressing room, her real hair is messy when she takes off her wig, then immediately neat and smooth moments later.
When the Inspector from Scotland Yard and Rock Hudson are walking down the gravel drive they are always in the sun, but once the camera cuts away to Geraldine Chaplin yelling a single sentence message to them, the camera cuts back to show them twice as far down the drive and on the other side of an enormous shadow.
When Jason Rudd is trying to find a pulse on a victim's neck, their eyes move although they are supposed to be dead.
There are people in front of the vicar's movie projector but they cast no shadows onto the screen while the projector is on. The screen is in fact backlit.
In the scene where Jason Rudd is driving away with his car, you can clearly see the chalked position marks on the ground that had been applied to place the car rightly for the shot.
Set 1953, Marty Fenn drives a 1959 model car.
The Courage Brewery sign outside the village pub is a late 1970s gold and red plastic one yet the film is set in 1953.
Though the film is supposed to be set in 1952, the car that Tony Curtis uses to deliver Kim Novak is a 1959 Cadillac convertible.
When the inspector first enters the house, he has a conversation on the stairs. There right in the centre of the screen, bellow the window is a very new shiny burglar alarm.
The houses in the village have UHF television aerials. In Britain, broadcasting on the UHF band did not begin until the 1960s, when BBC2 started.