Revealing mistake: Right after Jack and Will commandeer the Interceptor and are moving away and Commodore Norrington climbs the stairs and says, "Just get them in range of the long nines," you can see a jet contrail in the sky behind him. (00:47:45)
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: When Jack and Will commandeer the HMS Dauntless, the HMS Interceptor sails out with all her square sails completely square on (i.e perpendicular to the ships direction of travel) with the wind behind her. We then see the Dauntless sailing out of control in the other direction with her sails in the same position, the winds have switched 180 degrees. (00:47:55)
Continuity mistake: When Will is hanging from the mast while Jack is talking to him, the clouds in the background behind Jack changes more than normal during the shots. (00:48:00)
Revealing mistake: In the scene where Jack and Will have just taken the Interceptor and the Dauntless is coming about, the men on the row boat get caught in its path. A second after the men abandon ship, you see the boat get destroyed. If you look closely at the forward wake of the ship, the boat is too far away to be destroyed by the front of the ship. And since the boat initially goes down when it's struck, it can't be the keel of the ship, since that would send it up. (00:48:05)
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: Aboard Interceptor, Will says, "I'm not a simpleton Jack," Jack is near the wheel and tightening the line at the belaying pin on the rail. There's also a line going through a wood cleat on the rail next to the belaying pin. When Jack causes the boom to slam into Will, the rail is seen and the entire belaying pin with its line is missing, as well as the line in the cleat. Belaying pins are permanent and these are not flipped shots. (This is the wood belaying pin that snapped off, hitting Depp in the knee during the mishap, when filming Interceptor's escape.) (00:48:40)
Continuity mistake: Aboard Interceptor, the boom slams into Will and takes him out over the water. In the close-up shot of Will hanging there, the rope lines that are between Will's arms on the boom are not in the close-up shot of the boom, before it hit Will. Just the line to his left, can be seen in the boom shot. (00:49:35)
Continuity mistake: As the boom slams into Will, there's no pile of rope lying at the stern, only one line. In the next shot, Jack reaches down to pick up Will's sword and now there's a pile of rope lying on deck. When Jack swings the boom back and Will drops on deck, there's no pile of rope on deck again. This doesn't refer to the rigging lines attached to the boom. (00:49:35)
Continuity mistake: Aboard Interceptor, Will points his sword at Jack, and Jack swings the boom that slams into Will. In the side wide shot as the boom comes toward Will, when we see Will's hands as he grasps the boom, he is not holding the sword, nor do we see it drop or see it on the deck; however, we do hear it hit the deck. In the next shot, Jack picks up Will's sword near the line and rail, where it didn't exist in the previous shot. (00:49:35)
Continuity mistake: Aboard Interceptor, when Jack causes the boom to slam into Will, in that wide shot the belaying pin on the rail across from Will is seen. When Jack says, "But I can't bring this ship into Tortuga all by me onesy, savvy?" behind him to his left, the belaying pin is seen again. The lines hanging from that belaying pin differs in both shots. (00:49:35)
Continuity mistake: After Jack slams the boom into Will aboard Interceptor, then brings him back on deck, Jack points the sword at Will. In Will's close-up, the sharp edge of the blade actually faces Will's neck - the hand guard is at Jack's knuckles. However, in the next shot, a close-up of Jack, as Jack still points the blade at Will, BEFORE Jack flips the sword over, it is apparent that the sharp edge of the blade faces away from Will - the hand guard is at Jack's fingertips. (Though this is visible on the DVD, a better view is on the video.) (00:50:10)
Revealing mistake: When Will hangs on the boom over the water, Jack says, "I can't bring this ship into Tortuga all by me onesy.." Then he brings the boom back and Will falls. While Will lies on the deck, in both shots, a band on the bottom of the right leg of his breeches is seen above his leg hose, whereas in the previous shot when he was falling from the boom, the band in not there. (00:50:10)
Visible crew/equipment: Aboard the Interceptor, as Jack asks, "Can you sail under the command of a pirate...?" at the upper right corner of the screen, the corner of the crew's white reflector screen is perfectly visible in front of the boom. (00:50:15)
Continuity mistake: In Tortuga, as Will and Jack are seen for the first time, in the foreground is a drunk man teetering on two barrels and another drunk man on the ground drinking what is being poured into his mouth. In this wide shot the man on the ground has his right elbow on a sack on top of a small barrel. In his next close-up, the sack on top of the small barrel is gone and now there is a tied sack between him and the shovel. (00:50:50)
Continuity mistake: When Will and Jack are in the bar in Tortuga, Will stands with his back to the wall and on that wall is a shelf with a candle. The candle height changes and the candle drippings are very different in these shots too. Also, shots in the deleted scenes. (00:52:10)
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 the scene in Tortuga, there is a shot with the moon, really big. The boat passes in front of it with a pan and when the boat travels further on screen, you see the moon again in the front, very small. The shot made it look like there are two moons. (00:54:00)
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: When Elizabeth is dining with Barbossa aboard the Black Pearl, cutting between the front shots and side shots she holds the turkey leg differently in her left hand. Also held differently in her right hand is the bread when Barbossa offers her the apple and she looks at the monkey between the two shots. (00:55:10)
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