Other mistake: When Ariel is at the dinner table with Eric and Grimsby, Ariel takes Grimsby's pipe and blows it in his face, yet when he wipes his face there isn't any black stuff on his hankie.
Other mistake: After the storm, Grimsby helps Eric walk away from the beach while Ariel sings. Every time the shot back goes to those two they are on the same spot, though their legs move as if walking, giving the sense that they're on a treadmill.
Other mistake: In the last scene, where Ariel and Eric are sailing away in the boat, the rainbow in the background that Triton casts is backwards. It goes violet, indigo, blue, green, yellow, orange, and red. Very strange.
Other mistake: The outline of Flounder's body is constantly drawn over the top of his fins.
Other mistake: When Grimsby talks about the statue, the sailor behind Eric remains still, no animation at all.
Chosen answer: They are all throughout the film but the biggest one is when Eric is steering the ship to stab or skewer Ursula.
Disney-Freak