Continuity mistake: When a woman watering her plants notices the match below, the left shutter is open less between shots. (00:12:09)
Continuity mistake: When Mr. White says that Ash and friends appear to like Pokémon, his right arm is by his side, but in the next shot, it is raised to chest height. (00:14:07)
Continuity mistake: When Ash says it would be nice to go to Arborville, Pikachu's right foot is not past the railings on the riverboat, but in the next shot, it is. (00:14:17)
Continuity mistake: When Professor Oak turns one page in a book, his left thumb is four centimetres away from the top of the book, but in the next shot, it is eight centimetres away. (00:15:32)
Audio problem: When Ash and his friends arrive at the waterfall, Mr. White speaks, but his mouth does not move. (00:16:27)
Continuity mistake: When Ash and friends are first surprised that Mr. White's boat could fly, Misty's bag is closer to Ash, but in the next shot, it is closer to her. Also, Brock's hands are on the side of his seat, but in the next shot, they are on top of it. In addition, Misty's left hand is on her and Ash's seat, but in the next shot, it is not. Furthermore, Misty is next to Ash, but in the next shot, she is not. (00:16:33)
Continuity mistake: When Towa tells Ash and friends to stay where they are, the amount of space between each rung on a ladder is 15 centimetres, but in the next shot, it is 7.5 centimetres. (00:17:33)
Continuity mistake: When Ash and friends are surprised when they see blue light and a shrine, Ash's right hand is past his left, but in the next shot, it is the other way around. (00:19:04)
Continuity mistake: When Ash says, "Hey, it's a kid," Sam has his right foot over his left one, but in the next shot, it is on the ground. Also, Brock's left foot is on stone, but in the next shot, it is on moss. (00:19:22)
Continuity mistake: When Sam is confused after Ash asks who he is, the trees behind him change between shots. Also, Misty goes from being near him to being absent. (00:20:06)
Continuity mistake: In the shot where they first visit the Lake of Life, Sam wades into the water (all the way up to his waist). As he steps out, there is only water at his ankles, and moments later, there is no water. (00:34:56)
Continuity mistake: After the Pokémon are blown away, the front of Ash's hat changes from white to red. (00:46:03)
Other mistake: When showing "In Association with" in the English dub's credits, The Pokémon Company is misspelled as "The Pokeman Company." (01:15:37)
Revealing mistake: When Professor Oak is getting a book from a bookshelf, the book appears out of nowhere. (01:15:52)
Character mistake: When they find a Suicine, they ask Oak and he says it's a Swecon.
Suggested correction: I watched the film, and Professor Oak pronounces Suicune's name correctly.
