Continuity mistake: When Richard and Francoise are making love on the beach. They begin kissing deep under the water and continue all the way to the top. When they reach the surface they can stand up in the water which appears to be waist-level.
Continuity mistake: The photo that Richard downloads at the end is clearly not the one taken earlier. There are people in different positions, and one guy who was standing on the ground when the picture was taken is missing completely.
Continuity mistake: When they first get to the island and they are playing cricket, Keety is telling them all the rules of the game and asks "who doesn't understand?" Richard and Etiene raise their hands - when the angle changes, Richard's other hand is raised.