(at around 2 mins) During Nick's premonition, when the cowboy sits in front of Lori, something happens on the track which causes the audience to stand up and gasp. After Nick's premonition, the cowboy sits in front of Lori, but the audience remains seated.
(at around 49 mins) In the pool scene the pressure gauge on the drainage pump is shown in close-up to read 100-120-140-160 PSI, while on the far away shot it reads 70-80-90-100 PSI.
(at around 1h 11 mins) Nick is shot with two nails in the arm. In the next scene he has four nails in his arm.
(at around 39 mins) Nick says he can't be sure who is next to die, Hunt or Janet, because in his premonition, they were both killed in the same collapse. However, he is confident that George dies before Lori even though in his premonition, they were both killed by the same explosion.
(at around 1h 9 mins) After Nick has the mall premonition, he rushes through the mall to find the construction site. In one shot, you see him pushing through some people. For a brief second, you can also see Lori and Janet chasing him. They are supposed to be in the movie theatre.
(at around 1h 13 mins) The sprinkler system that saves the movie theatre would not work. Water cannot put out a chemical fire, you would need a foam system, and not only would it not put it out but it would spread the fire and make it wider.
(at around 1h 8 mins) During the escalator scene, Lori's right foot was crushed by the escalator's conveyor belt. This makes her spit out blood, and that is not supposed to happen. Since only her limbs were hurt or injured, she wouldn't spit out blood. We only spit out blood if our head, chest, or abdomen are injured or hurt.
(at around 1h 11 mins) A nail gun cannot shoot without the trigger being pulled back, and the front end (where the nail shoots out) being pushed into the wood; furthermore, electric nail guns have to be within certain angles in order to shoot. It would be impossible for the gun to shoot like it did in the film.
(at around 1h 11 mins) When the nail gun punctures the drum of flammable liquid, the drum is clearly labeled with a "4". Class 4 hazardous materials are flammable solids, not liquids.
(at around 1h 12 mins) Sprinklers work by holding back water with a heat sensitive liquid filled glass bulb or soldered struts and the heat from a fire burst the bulb/melts the solder allowing water out. In the film the sprinkler head is open, with no bulb or struts so the system must be drained down and the main valve shut, or water would constantly be flowing.
(at around 57 mins) In the hospital scene when the bath is overflowing, there is a massive amount of water pouring out of the bath, but only a small stream going into it from the tap. It would be impossible for more water to be coming out of the bath than going in.
(at around 1h 13 mins) After Nick sets off the sprinklers by waving a wooden stick on fire at them, you can see him twitch and slide around his other arm slightly, which is supposed to be nailed to the wall and therefore immobile.
(at around 45 mins) In the car wash scene, Janet is shown trying to call for help but is unable to since there is "no signal", but when the phone is shown, "Offline" can clearly be seen on the upper corner of the screen. This is only displayed if the offline mode (used while traveling on airplanes) has been manually enabled.
The bathtub that killed the cowboy was overflowing over his bed but somehow moved when he got out of his bed.
At 32:35, the shot of Lori (Shantel VanSanten) when she looks at Nick (Bobby Campo) - she shot is obviously in reverse.
In the 18th minute at the vigil, a couple thanks Nick for warning them. On the male, his makeup line is clearly visible below his hairline.
The newspaper that reported about Samantha's death said the rock went through her head at "Light speed"
George refers to the champagne they are toasting as apple cider.
During the "Greatest Kills" when Rory's death is shown his arms are up, but in Final Destination 2 his left arm resting to his side causing it to get cut of.
Cheyenne tells Samantha that someone was killed on their block the previous evening. Carter was killed on a different street, a residential one (which this is not).
There is no explanation for why Andy speaks from inside the thick fence to the other three, who standing on the outside.
Samantha asks the receptionist for a glass of water as she's getting her hair done, but she calls her by the wrong name. She calls her DeeDee, who is the girl giving her the haircut. The receptionist is named Cheyenne.