Continuity mistake: Near the start, Percy says "Boys upstairs and down on your left, girls the same on your right". However, after the three heroes have been to investigate Fluffy and they go back to the dorms, when they reach the top of the stairs Hermione goes to the left and the boys head right. (00:49:30 - 01:03:30)
Suggested correction: Incorrectly regarded as a mistake. The spiral staircase that leads up to the dormitories ends on a landing that is oriented at a 180 degree angle from Percy's position when he speaks the line. Coming up the stairs to the dormitories (and pointing the camera) from the back side (looking over/toward the common room from the landing) means that left and right are reversed from the camera's point of view in the second scene. Harry, Ron and Hermione go into their appropriate dormitories.
Continuity mistake: At the end-of-the-year feast the Slytherin banner is green and gold, but their house colors are green and sliver, as evident by their robes. (02:11:00)
Suggested correction: But the problem here is, you only see the banners once (as the shot pans down at the start of the scene) before they are changing to Red and Gold of Gryffindor. In the first show they are Silver and Green.
Continuity mistake: In the scene where Harry figures out that Hagrid got his dragon egg from "Snape"(Quirrell), at the begining of the scene, Harry's cloak is buttoned and still is when he, Hermione, and Ron are running to Hagrid's hut. When he reaches Hagrid's hut, it is unbuttoned even though he never unbuttoned it himself. (01:46:50)
Continuity mistake: When Dudley pops up after Hagrid gives him a pig's tail, his face and hands are clean, even though he was just eating Harry's birthday cake with his hands. (00:16:40)
Continuity mistake: In the scene where the pupils are waiting on the stairs before being sorted into their houses, Malfoy speaks to Harry and is clearly at the top of the stairs. However as the pupils go into the dining room, Malfoy is nowhere to be seen in at least the first 30 pupils. (00:41:15)
Suggested correction: That is because McGonnigal taps him on the shoulder, and he walks off down the steps to back with Crabbe and Goyle.
Other mistake: While Harry and his classmates are on their way up to Gryffindor Tower right after the Sorting, Neville reacts with astonishment to a portrait moving. However, we learn in later films that Neville was raised in a magical household (by his grandmother), so he should have been completely accustomed to seeing pictures move. (00:46:30)
Suggested correction: Not every magic household has moving pictures in the house.
No, but being raised in the magical world he will have come across moving portraits. A good example (tho not explained until book 5) is at St Mungo's. He visits his parents regularly. The hospital has portraits there that would move. Thus seeing the one move at Hogwarts shouldn't have startled him.
I am now doubting it's Neville who is saying it. Can't be sure it's his voice. It can also be he is mentioning they are portraits, not photographs that are moving. Maybe moving paintings are rarer.
Continuity mistake: When Harry, Ron and Hermione go to the third floor corridor for the first time, they all run into the corridor with Fluffy in and close the door. In the next shot, Ron walks through the door again and closes it again. (00:59:40)
Continuity mistake: When the letters start flying through the letterbox they are coming in with the address facing down and the red seal facing up. When Vernon says they are going away, the letters are now addressed side up and red seal down. (00:12:15)
Suggested correction: This is not a mistake. The letters are magically arriving en masse, in batches, pouring in at a rapid speed, and are flying about everywhere. Some naturally are facing up and others are face down as they come through the letter slot.
Other mistake: Percy Weasley is obviously talking to the Gryffindor first years when they first enter the Gryffindor common room, but there are too many first years. There are 5 boys and 5 girls in each dormitory, so 10 first years in each house, but in the shot there are obviously almost 20 students there, not including Percy. (00:47:30)
Suggested correction: While each room does only fit 5 students at a time, the movie did not state there is only one room for each gender per year. We don't see all of Gryffindor tower and have no way of knowing if there is only one room for first year boys/girls.
