Audio problem: At the blacksmith shop, just after Jack says, "You need to find yourself a girl mate," Jack pulls an all wood mallet from the wood ledge above and it actually makes a long metallic rasping sound, which is completely out of sync with the action. In a previous shot Will does a somersault and he grabs a sword hanging from the wood post. When he pulls it off the all wood ledge, it too makes a sharp metallic rasping sound. This is obviously done for dramatic effect. (00:24:25)
Deliberate mistake: During the pirates' attack on Port Royal, when they go about cutting and slicing, it is very obvious many times, especially in close-ups, that fists, weapons, etc., do not make contact, and the victims usually have a delayed reaction or react before actually being hit. This type of thing occurs numerous times aboard Interceptor, on Tortuga, and Isla de Muerta. (00:31:20)
Continuity mistake: When Jack is knocked out by the bottle he has one hand raised with a gun to shoot Will but when he is seen on the ground both his hands are up by his head. The gun-hand yes, fine, but the other one would be by his side or in a different position at least.
Continuity mistake: Will has a small tear in his shirt at the right shoulder. Sometimes it's bigger, sometimes it's smaller, and the shape changes throughout the movie. (00:48:30 - 01:22:50)
Continuity mistake: As Jack and Will are duelling while standing on the cart, and then up on the beams, in wide shots, Will's hair is pulled back perfectly in the ponytail, but in the close-up shots he has loose hair on the sides that is not held in the ponytail. This type of thing occurs numerous times in the film. (00:25:20)
Revealing mistake: During the first blood ritual and other moments in the film, you can tell that Geoffrey Rush's (Barbossa) eyes are yellowish only because he's wearing colored contact lenses. (01:12:45)
Plot hole: In the shot where two of the pirates find Jack Sparrow in the prison, you see the moon shine out over Port Royal and the pirate's hand around Jack's neck is skeletal. While this is happening we know that Elizabeth is being led onto the Black Pearl by two pirates. If the pirate in the prison turns skeletal, why don't the pirates with Elizabeth turn skeletal? It's clear that they don't as Elizabeth only discovers the curse later on aboard the Black Pearl.
Suggested correction: This can be explained that on the route from Elizabeth's house to the ship there is a lot of fog, smoke from fires and gunpowder explosions, so the moon doesn't get through. The moon only get through once they are underway again and the fog is cleared. The prison is much further and higher than the town and so the moon does get through (only sometimes) there.
You're very much mistaken. In later scene pirates turn skeletal when marching underwater, at the bottom of the ocean. Moon is easily able to get through water and this smoke isn't thick enough to block the moon.
How does water compare to fog? Of course the moonlight comes through the water, its transparent. Fog isn't transparent. You can go technical and question how much the moonlight is reflected away before the effect wears off, but obviously the effect wears off when there is no direct moonlight hitting them, as is the case with fog and smoke.
Continuity mistake: In the scene when Jack is on the Interceptor for the first time a white X is formed with straps on the guards' uniforms. A few minutes later the strap moves up 3 buttons.
Continuity mistake: Just after Jack and Will have duelled, Jack gets knocked out by the drunken Mr Brown. Norrington looks at Mr Brown and says his line, yet when the camera cuts to a different view, he is now looking at Jack and not at Mr Brown. (00:25:55)
Continuity mistake: Elizabeth holds the medallion chain over the edge of the railing. In the first shot she says, "I'll drop it," the chain dangles down with the excess chain over her fingers. In the front close-up of her arm, only the bottom chain is dangling. In the back close-up of her hand, with Barbossa in the background, the medallion and chain dangle shorter now, with the excess chain over her fingers. This takes place before she says, "There's no point in me keeping it." (00:38:50)
Continuity mistake: The right side of Elizabeth's face is twice slapped very hard (first by Boswain and second by Barbossa) but she never has a noticeable bruise, swelling, or other injury to her jaw or cheek.
Continuity mistake: When Elizabeth is taken aboard the Black Pearl, Bo'sun slaps her face. Bo'sun's hand never makes any contact with Elizabeth's face, but the sound effect makes it very convincing. Also, in the first side shot of the slap, when Bo'sun starts to say, "You'll speak..." it's the back of her left hand that touches her cheek, and we can see the white corner of her night gown under the robe sleeve. In the next front shot, it's the palm of her hand that is touching her cheek now and the white night gown doesn't show at the sleeve. (00:38:10)
Revealing mistake: After Will throws the small axe at the pirate and it hits him, he picks it up again and runs away. But the axe has no blood on it. The pirates do leave blood on weapons, as shown when Elizabeth stabs Barbossa later.
Revealing mistake: After the pirates open the gate on the Governor's property, they run towards the mansion and in the shot from behind they are casting shadows on the ground to their right. In the next shot from Elizabeth's window, they are casting long shadows directly in front of themselves. (00:31:55)
Continuity mistake: Anamaria's hat is turned, so the flap is on the side of her face when she says, "It was a good plan. Up till now." In the shots before and after, the flap of her hat is in the front. (01:23:00)
Continuity mistake: The position of Barbossa's white shirt collar varies within wide and close-up shots, during the first blood ritual with Elizabeth. (01:10:05 - 01:14:40)
Continuity mistake: When the Pearl chases the Interceptor the sea changes frequently from rough, to (relatively) calm sea. That cannot change that rapidly.
Other mistake: When we see Jacoby lying face down with the axe in his back, we can see how far the axe sticks out. It's not deep enough in his back to stick out with that weight of wood and metal. That axe would never stand upright, it would fall to the side.
Continuity mistake: When Elizabeth is dining with the captain of the Black Pearl, he takes out the medallion, and the medallion's position changes during shots on his hand. (00:53:40)
Continuity mistake: After Jack tells Will, "Nice hat," he starts to run up the stairs. Next shot, Will smiles and behind him Norrington starts to run towards Jack. In the next shot, Norrington is already up the steps with his sword held high, pointed at Jack, who shouts, "Friends." Then, when the camera faces the crowd, Norrington is still lower and his sword is down. In the next close-up and wide shot, Jack's at the top of the stairs, with Norrington higher up again, sword held high, pointed at Jack. This is not because of camera angles. (02:09:20)