Continuity mistake: In the scene where Mercedes confronts Edmond for the second time and he finally admits who he is, she makes a point of showing him the string still tied to her ring finger. Two scenes later, it is also visible when she is still asleep in bed. However, in the scene after she has been shot and everyone is tending to her, her left hand is shown several times and there is no string. Considering her statement that it would, "never leave my finger," and her later reiteration of that in addition to, "and it never has," for the 16 years she was separated from Edmond, it is strange that it has suddenly disappeared.
Continuity mistake: When Edmond goes to Fernand for help, they end up fighting in something similar to the living room (it's quite a big room). After the police take Edmond away, he throws his sword, but it hits the fake wall that is supposed to be the living room behind him and it's easy enough to tell that the room behind him is not real.
Continuity mistake: Edmond Dantes has just spent several years digging a tunnel through the rock walls of Chateau d'If. Yet when he washes up on the beach, a close-up of his hand shows us perfectly clean, manicured fingernails. Salt water may wash your hands clean, but it certainly won't trim, file and repair broken fingernails for you.
Continuity mistake: When Edmond Dantes is being swung back and forth to be thrown over the cliff the seams of the body bag are on top. However they show him looking through the seam as the bag is swinging as if the seam is on the side. He would have only possibly been able to see at the furthest point away from the keys yet the view of the keys is clear as the bag is swinging closest to the keys. On top of this the angle of the view of the keys would mean his head would have to be in the middle of the bag to be lined up with the keys. In the next shot his hand is lined up with the keys.