Deliberate mistake: As was admitted on the commentary, the angle of the moonlight in the stateroom, which has a deep overhang outside of the doors, was deliberately vastly exaggerated, to enhance the shots with Governor Swann battling with the disembodied skeletal arm. (01:56:25)
Continuity mistake: As the Interceptor sails away from the Dauntless, Norrington, aboard Dauntless, is standing in front of the wheel looking out towards the Interceptor. In the next shots, the Dauntless is colliding with the boat and in the background the Interceptor can be seen going in the opposite direction. Then back on Dauntless, Norrington is still looking towards the Interceptor in the same direction as before, however wrong that is, and acknowledges the comment, "That's got to be the best pirate I've ever seen." (00:47:45)
Continuity mistake: Pintel and Ragetti walk into the stateroom, Pintel carries the folded dress for Elizabeth in his arms. She walks over to them. In the next shot, the folded dress is now folded differently in Pintel's arms. Also, when they tell her she'll be dining with the Captain, Ragetti's collar is under the strap on his shoulder. After she answers them, in their next close-up, his collar is straight and over the strap. (00:54:15)
Continuity mistake: At the Fort, the two columns of soldiers separate and Norrington walks into view. It's shouted, "Right about face," and the soldier behind Norrington on his left has his black bag to his side. When "present arms" is shouted, the soldier's black bag is in front. Also, Governor Swann, in the front wide shot, is standing on the second step from the bottom. In the next close-up, he's standing on a step further up - the soldier to his left in the previous shot was standing on the same step as him. (00:11:15)
Continuity mistake: After Elizabeth whacks Jacoby and tells him to try wearing a corset, she helps Will to his feet. In the close-up of Will smiling and looking at her, his hair is noticeably wet and very stringy. However when Elizabeth asks, "Whose side is Jack on?" Will's hair is no longer wet. (01:59:50)
Revealing mistake: The medallion's necklace has very narrow bar links, with one loop link at the end and it's not adjustable at all. When Elizabeth wears it in some shots, the necklace hangs much shorter, for example during her failed blood ritual. As the medallion falls into the Aztec chest during Elizabeth's ritual, the chain is even shorter. In other scenes it's long enough to tuck into her bodice as in a later scene aboard Interceptor with Will, when she gives him the medallion. When Will wears it, it's again much shorter, which can not be excused because he has a man's neck. The clasp closure is seen intact and it's not adjustable. It's simply a few different length necklaces used. The necklace gets ripped off, but that's also not an excuse for the length difference because as noted in another mistake the type of closure it has makes that impossible to do. (01:11:15 - 01:18:20)
Continuity mistake: At Jack's hanging, Will draws his sword and shouts, "Move!" The next shot is of the crowd in front of him parting and there is a clear view of the hanging scaffolding. Then in Will's next shot, we see the same crowd from the front, parting again as Will throws the sword into the falling trap door. (02:06:15)
Continuity mistake: Jack escapes the brig of the Black Pearl, goes up on deck and grabs the line from another and says, "Thanks very much." This shot's flipped. In the next wide shot of Jack (Tony Angelotti), he grabs the line again and swings across. The flipping was done in order to keep the Interceptor on the left of the screen and the Black Pearl on the right of the screen during the fight sequence. (01:28:15)
Continuity mistake: When the Interceptor drops its anchor on the right side to surprise the Black Pearl, Barbossa turns to the crew and yells, "Hard to port. Rack the starboard oars." When he says this line, his teeth are either normal, or not nearly as gross as they are in the rest of the movie. [Fixed on Blu-Ray]. (01:24:40)
Continuity mistake: Aboard the Pearl (before Elizabeth's blood ritual), in the exterior shot Elizabeth peers out the window which slants away from her right side - making it the right window of the port side, as she faces it. However, in the next interior shot she actually sits in front of the port side's left window, which slants away from her left side.
Revealing mistake: Jack and Elizabeth are marooned on the island, and he goes down the stairs to the cache of rum. From below, he lifts his right arm up holding a bottle of rum and we see the pirate brand. It's a CG brand, and in this shot, the pirate brand is crooked and off to the side. It doesn't look the same as the close-up when Norrington lifts Jack's sleeve in Port Royal, and it's not because of camera angle. Jack's sun and sparrow tattoo isn't where it's supposed to be either. At this point in filming, this 'tattoo' on his arm is not a real tattoo, it is only applied for specific shots, and make-up didn't apply it for this shot. (This has nothing to do with Depp's real tattoo that he supposedly got later, after filming.) (01:36:15)
Revealing mistake: Will walks down the stairs, after the coach leaves and the cottage to the left of the Governor's mansion isn't seen at all. In this close-up, the Governor's mansion behind Will is only a facade built at Marineland. They only built the facade for the main house, not the two servants' cottages on both sides of the mansion. In the next wide shot, both cottages and the mansion seen, are miniatures used in a CG composite on the hill. Given the proximity of the (miniature) cottages at both sides of the house in the wide shot, the left cottage should've been seen in the close-up, but obviously couldn't because the cottages weren't built. Fuller view of the wide shot in deleted scenes. (00:08:45)
Continuity mistake: On the docks, when Norrington exposes Jack's scar and tattoo on his right arm, he says, "Well, well, Jack Sparrow, isn't it?" and in the wide shot Murtogg holds the middle part of his gun. In the close-up when Murtogg says, "He said he'd come to commandeer one," he holds it near the bayonet, yet in the next wide shot he holds it in the middle again. (00:17:40)
Continuity mistake: When Jack and Will are dueling in the blacksmith shop on the cart, Jack falls onto the ground. Then we get a close up of him shaking his face, watch the bone in his hair, it's bent. Then he stands up again and the bone is straight. (00:25:40)
Continuity mistake: When Jack arrives at Port Royal, he stands in the sinking boat, trying to bail out the knee-deep water. When he steps onto the dock, he is completely dry.
Factual error: Sir Charles Wheatstone, an English physicist (b.1802 - d.1875), invented the 'concertina' around the mid 1800's. The 'concertina' is a small musical instrument like an accordion, with bellows and keys. During the Moonlight Serenade scene, when Elizabeth walks out onto the deck, she sees the skeletal pirates for the first time, and Jacoby is seen playing the 'concertina', but it was not invented yet. (00:58:45)
Continuity mistake: In Governor Swann's home the maid runs past the dead servant and out through the front door, the camera begins to pan the interior and we see the foyer. There's a chair, a table and to the right is the overturned chair and the table is right next to the legs of the overturned chair. Then as Elizabeth, Pintel and Ragetti watch the cannonball crashing through the front window, the table is now much further away from the overturned chair. No one touched the table or chair. (00:33:00)
Revealing mistake: Jack says, "Or you could surrender." Soon after, Barbossa smacks Jack in the face and we can see Jack's wig and red forehead scarf coming off his head, as he's going down. You can clearly see Tony Angelotti's (Depp's stunt double) forehead, sideburns and hairline in the right hand corner of the screen. (The shot right after this one is Jack running with his arms waving.) (01:57:15)
Continuity mistake: When Will first sees the hammer it's lying on top of the anvil almost parallel with it. Right before Jack says, "You know what you're doing, I'll give you that," as Will sticks his sword towards Jack's legs, the hammer's seen to Jack's right, perpendicular to the anvil. In the next shot, when Jack actually says those words, the hammer's lying parallel to the anvil again. Jack says, "If I step here," and the hammer's perpendicular to the anvil again. Then in the next few shots, once again the hammer's parallel to the anvil. Even in the 'parallel' shots, the hammer's lying a bit differently. (00:22:25)
Continuity mistake: At Jack's hanging, when Elizabeth "faints" her hat's wide white ribbon hangs down both sides - joined at the back of her neck. When she lifts her head, to witness Jack's rescue in progress, the ribbon is now gone from the right side of her hat and hangs loose at her left shoulder. However, when she looks over at her father, the ribbon is intact once again. (02:06:15)
Answer: The curse needs the blood of everybody who took a coin from the chest. All the other pirates have already contributed so, as the movie opens, the only blood needed is Will's, substituting for his father. During the finale of the movie, Jack takes a coin from the chest, adding himself to the curse, so his blood is now required as well as Will's.
Tailkinker ★
But I didn't see any blood on the coins, and none of the pirates cut themselves, even before Will became part of the mix.
Yes, the other pirates did cut themselves before Will came into it, off-screen. The lack of blood on the coins can simply be explained as most of it dripping to the bottom of the chest, it being washed away by storms blown into the cave, or by the fact that they didn't drop that much blood on it in the first place.
When they had Elizabeth they believed she was Bill Turner's daughter, but they all thought the curse had failed, none of them had cut themselves so it makes zero sense.
They had been collecting back the coins for years. During that time they repaid their own blood. All they needed was the last coin and the blood of Bill Turner to break the spell.
lionhead