Continuity mistake: While Howie is painting a hare with Myrtle, at the moment he says "Do you know Rowan?" There is a dark coloured paint brush standing in a pot, next to a red and green paint pot. Also there is a pencil under Myrtle's left arm. Seconds later the paintbrush has changed to yellow, there is a grey paint pot next to the red and green pots and the pencil under Myrtle's left arm has gone. (00:15:15)
Continuity mistake: Edward Woodward's Sergeant Howey is aroused by Britt Eckland's Willow on the other side of the wall and touches the wall and jogs a picture so that the bottom shifts rightwards so that the picture is not straight. Then the sergeant edges backwards and the picture is straight. (01:02:30)
Other mistake: During his conversation with the landlord of the pub he ends up staying in, Sergeant Howie makes it clear that he did not intend to stay on Summerisle overnight, that he had been delayed and so needed accommodation. Makes you wonder why he packed his pyjamas. He's wearing them when Britt Ecklund does her famous naked song and dance routine, and they are not new so we know he didn't buy them that day. When he arrived he didn't even think he'd be on Summerisle for more than a few hours - we don't see him with so much as an overnight bag.
Visible crew/equipment: In the director's cut, there's a scene where the bar-owner is tied up to the bed. A few seconds before it cuts away, a crew member's leg can be seen on the left hand side.
Continuity mistake: Near the end when Howie is in the cage and praying, one shot shifts to the line of watching islanders. Summerisle walks towards them, turns and signals with his left arm. Cut back to Howie in the cage, then back to the islanders. The same sequence of Summerisle walking and signalling is then shown again.
Continuity mistake: When Sgt Howie is unable to start the plane, he calls the harbour master. While the harbour master is rowing back he calls out to Sgt Howie "what's the matter, won't she go?" Notice that when he begins this question he is nowhere near the plane, but as he is finishing the question, he is now alongside the plane.
Plot hole: Could Howie have not telephoned for more officers? When Howie first walks into Summerisle you can see poles that are used to carry telephone lines. Later on you see outside The Post Office (May Morrison's shop) a box that is used an exchange box for telephone lines in the town. The story gives us the belief that there were no telephones on Summerisle, which is why Howie was unable to send for help. But there is clear evidence of a telephone network on the island. Even if the islanders somehow manage to prevent him making a call, what about the radio on the plane?
Revealing mistake: Edward Woodward goes to visit Christopher Lee at the big house. In the grounds, a group of pregnant women are performing a pagan ritual involving jumping over a small bonfire. Woodward the Christian puritan looks out of Lee's window and sees this, and exclaims indignantly: "Those young women are NAKED!". In fact, even on a 14-inch TV screen you can see that they are wearing fleshtone body-stockings.
Continuity mistake: When Sgt. Howie first goes to the Post Office, he walks through to where Myrtle is painting the hare. He puts down his leather case which then changes position a few times during the next few shots, until the scene ends.