Ssiscool

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)

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 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 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)

Grumpy Scot

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)

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)

Corrected entry: When Harry is searching the restricted section, he puts the lamp down first and then the cloak. So the cloak would be on top of the lamp, but when he pulls on the cloak so he can put it on, the cloak is under the lamp.