Best horror movie mistakes of 2001
Factual error: When Brendan Fraser & his son are running to reach the pyramid before the sun hits it, the sunrise line approaches the pyramid along the ground, but the sun would naturally have hit the pyramid at the top first and worked its way down to the ground. [Some people insist on trying to correct this - think of it this way. If the sun's illuminating the ground from way up in the sky, what's keeping something higher up than the ground in darkness?]
Factual error: Burt claims his watch updates its time "by connecting directly to the cesium clock in Colorado via ultrasonic frequency." Later the graboids home in on him by the ultrasonic sound emitted by his watch. Firstly, radio controlled watches update their time by receiving signals, but they don't emit any signals - the battery would be way too weak for two-way communication. Secondly, they work on radio waves, not sonic waves. Thirdly, if a hypothetical time transmitter did work on ultrasonics, the smallest distance between Colorado and Nevada is some 435 km (around 270 mi). An ultrasonic signal strong enough to reach that far would probably be deadly within a sizable range around the transmitter.
Continuity mistake: During one scene in the film Bones' girlfriend is looking at an old picture of her & him. You see her holding the picture and Bones turns and looks at her and she screams and she drops the picture. At the end of the movie the main character finds the picture and is looking at it. Bones once again turns his head and looks at the person. However, it's the same clip as before because you see a woman's hand with red nail polish holding the picture.
Continuity mistake: The first time we see the young doctor doing his "lobotomy" in London Hospital (to the girl that was married to Prince Edward), Ian Holm comments on the procedure for some guest as they stand behind a glass window. You can clearly see the young doctor doing the third strike with his hammer in a reflection in the window. The movie cuts back to the young doctor and he is doing the third strike for a second time.
Continuity mistake: At the end when Dana fell off the roof, notice the scars on her face when she rolls off what used to be the Djinn. At first, they are simple scratches. When she gets to the roof of the building to find her boyfriend, the scars are deep scrapes. Then in the final shot they are back to simple scratches again.
Continuity mistake: When Kim is being chased through the woods by the attacker, she finally notices a shelter in the distance and runs towards it. As she stops in a clearing closeby, she is suddenly faced by the attacker who stabs her in the stomach with a machete. In the shot her right backpack strap has fallen off of her shoulder and is down to her elbow. But in the next shot of her falling backwards to the floor, the strap is suddenly back on her shoulder.