The exterior of the door to Darlene's hotel room is made of solid vertical panels but inside the room, when Darlene opens the door, it is now of a glazed type that would be used for access to a balcony or a patio.
When Sandra is shown bound and gagged lying in the boat, the boat's deck is of a slatted design, but when the boat is seen from above as it nears the island of Tramiros, the deck of the boat's cockpit is solid and too small for anyone to lie down on.
Sandra and Darlene are shown emerging from the water after their fight but it is only Sandra who is dripping wet - Darlene is almost totally dry, probably the result of a stunt woman replacing Jayne Mansfield who was reportedly pregnant at the time.
When the hotel manager is walking along the corridor to Darlene's room, this looks like a set because none of the doors have numbers, locks or door handles - surely necessities in a hotel.
At the start of the film when Lylle Corbett is pushed over the cliff, a dummy is used.
When Livio Morelli arrives on the island, he hides the boat by pulling some branches from nearby trees but it can be seen that the branches have been cut beforehand.
When Darlene is asked to turn down the volume of her radio, she touches the end panel of the radio, but the volume control is actually on the top of the radio; but despite this, the volume decreases as she walks to answer the door.
When Corbett supposedly pushes him into the wardrobe, it's obvious that Kostis has plenty of room to escape, but turns round and, despite his protests, steps in himself, so Corbett can kick his rump before shutting the doors.
Lylle Corbett (Cameron Mitchell) makes no attempt to clean up his head wound which would be a natural reaction, but instead leaves it unattended, which in a hot climate like Greece would invite serious infection, leading to serious illness or even death.