Continuity mistake: When Malfoy and his friends bother Ron and Hermione, Harry shows up and messes with the three boys. He grabs hold of Malfoy's feet, lifts them in the air and pulls him across the snow. In the first close-up of the soles of Malfoy's boots, not a speck of snow is on them, though he was just walking in it. Then in the next close-up, his feet still in the air, the soles are now covered in snow. (01:02:45)
Continuity mistake: While Ajax and Hector fight, Hector head butts Ajax, and three shots later in a wide shot, half of the hammer end of his unusual spear actually breaks and falls to the ground behind him to his left. But lo and behold, in the next close-up the bloody hammer end (bloodier than the previous shot) of his spear is whole and intact. (01:20:00)
Continuity mistake: The hull numbers of the Constellation change throughout the film between CVN-74 and CVN-68.
Continuity mistake: When Hutch tackles Starsky to the ground after his gun goes off in the disco, Starsky's badge falls to the ground beside his head. Hutch grabs it and holds it up, telling people to calm down, but when the shot returns to Starsky the badge is still there next to his head. (00:49:40)
Continuity mistake: When Napoleon is waiting while Rico makes a sale, he checks his watch to see how much time he has before the dance. The first time he checks it, the date on the watch indicates Thursday July 17. When he checks it again a few minutes later, it shows Monday July 21.
Continuity mistake: When Hellboy is walking at one point, holding his gun up in his left, gloved hand (just after one of the agents has said "This place is like swiss cheese"), watch the frame. It switches suddenly so his right hand (the stone one) is his left, and he's holding the gun in his "right." (00:59:40)
Continuity mistake: In the scene where Mindy is showing Spongebob and Patrick "Planktopolis," it shows a large fully-built statue of Plankton. A few seconds later the right side of the head is shown missing and still being worked on.
Continuity mistake: When Jack is briefing the President, he draws a line on a map of the U.S. and tells the President to have everybody south of that line evacuated. The shape of the line changes between shots. (01:04:20)
Continuity mistake: In the opening scene, Mort closes the door of his jeep before he goes into the hotel room. You can hear the sound of the door closing and it's visible in the rearview-mirror. As the camera moves out of the room, the jeep door is completely open. (00:02:05)
Continuity mistake: Towards the end of the film, Mattie hands Jenna the dream house he made for her 13th birthday. There is hardly any "wishing dust" on the roof. However, when she goes outside and sits on her front porch, there is plenty of wishing dust all over the roof of the toy house now.