Revealing mistake: After the military attack Sao Feng's residence, when Elizabeth is seen fighting amid the melee the black spandex-like shorts are visible under her robe as she kicks up.
Revealing mistake: The outline of Pintel's yellow contacts are obvious in some of his close-ups, depending on his facial expressions, such as when he speaks of the green light as they sail towards the Locker.
Revealing mistake: Throughout the movie, the edges of Barbosa's yellow contacts are easily visible (especially in the scene where he orders Calypso to the brig).
Revealing mistake: At the beginning of the film, when Sao Feng is introduced, a couple of his real nails are visible under the fake long dirty ones glued atop them. It's most noticeable when he scratches his head.
Revealing mistake: Just after Barbossa and Elizabeth reach Sao Feng's residence, down below when Gibbs pulls the bars they actually bend.
Answer: He agreed to do a job in exchange for eternal life, with a few limitations. If he refused to do that job he'd be cursed until he fulfilled his duties, but that doesn't excuse him from the details of the previous enchantment. He didn't simply choose not to walk on land, he couldn't.
Phixius ★