Paul Henderson's coffin opens on the right side to attack Inspector Holloway. Later, the coffin opens on its left.
When Charles is standing on the bridge holding the crumpled picture of Dominick, the water beneath the bridge is still. When the picture lands in the water, it lands in flowing water and is washed away.
After Carla is bitten by Paul (the vampire) she conceals her neck as she flees. The next day there are no bite marks on her neck, despite her complaining about having been bitten.
The "Daily Express" newspaper that Sgt. Martin is reading is dated Monday, June 8, 1971. In 1971, June 8th fell on a Tuesday.
As the inspector walks down into the cellar he's holding the candles to his right, yet we can see his shadow on his right as well.
The axe the waxworks owner uses to kill Philip Grayson bends like it is cardboard or a fake axe.
Holloway is supposed to be going to the house during the night at the end of the movie, but it's clearly day when he does.
When Charles (Denholm Elliott in the first story) takes the book from the shelf, he visibly blows once to remove the dust, yet the distinct sound of 2 blows is heard.
Black wires are clearly visible above Carla as she rises up to the second floor to bite Paul after she becomes a vampire.
Wires can obviously be seen when Paul is levitating in the air.