Revealing mistake: When Hiram, Juan and the boys are camping out on their way to the mine, one of the cowboys is hit by a couple of Dirt Dragons (one from either side) as he runs to the others. His body is tossed one way, then the other (as they hit him), but then sort of 'jerks up' against gravity, indicating he is being lifted by a wire. (00:24:55)
Continuity mistake: When Gummer and Black Hand Kelly make an agreement, Kelly looks to his left and he isn't holding a glass. When it cuts, he is looking to his right and holding a glass. (00:40:35)
Continuity mistake: When they are talking with Black Hand Kelly, there is a shot where Lord is looking down. When it cuts, she is staring right at Gummer. (00:41:00)
Continuity mistake: When Hiram, Juan and Kelly first see Old Fred's wagon in the distance, the white tarp on it is draped across it and down one side. When they arrive at it, it's draped differently. They also arrive at it from the side, when they were approaching from straight in front on it. (00:46:15)
Continuity mistake: As the trio are bedding down for the night in the muling station, we see Juan walk behind Hiram who is standing still; the camera angle changes, and we see Hiram walking in front of Juan, who is now the one standing still. (00:50:05)
Continuity mistake: When the Dirt Dragons show up at the muling station, after the trio shoots at them, Kelly is emptying his gun of the used cartridges, but then they turn to shoot it behind them - Kelly doesn't reload, but is shooting. There's only about 2 seconds for Kelly to open his jacket, pull out more bullets, load the gun and fire - not enough time. (00:51:55)
Factual error: In the muling station, Juan is at the telegraph when a Graboid comes up from underneath him. As he is flung up into the air, he 'hangs' there for just enough time to disprove the law of gravity. Also when the Graboid breaks through the floor, it is just behind Juan, which would have sent him forward (over the telegraph) - yet he is thrown backward. (00:57:30)
Visible crew/equipment: This movie is set in 1889. There are clear deep truck wheel tracks on the road when Gummer is about to leave Rejection. The steam tractor's wheels are too wide to make these tracks. (01:05:30)
Continuity mistake: We see Hiram loading the shot in the punt gun - then the camera shows each character loading their gun, and then the punt gun is being loaded again. (01:16:50)
Revealing mistake: At the end of the movie, when the last "Graboid" appears, in one or two shots of him retracting back into the ground, you can tell the shots are reversed, as dirt is being sucked down in an unnatural way. It flies up and sort of "implodes" towards the creature. (01:23:50)
Continuity mistake: It is established in the film that the Graboids have 3 'tongues' - but when the women are trapped in the wagon, they shoot two of the tongues of the Graboid hunting them, then two more tongues come out of it. (01:28:35)
Continuity mistake: Right at the end when the last monster is in its hole, we can see a large part of its body. When it cuts only a small part of the monster is sticking out of the ground. (01:28:40)
Other mistake: At the very end, when a man is painting the "F" of the city's new name on the water tower, with white paint, you can see that though the brush is white, and it is touching the surface of the water tower, no paint is left on the surface of the water tower. Nevertheless, the painter continues painting the letter in the next shot, even though no paint is left on the surface. (01:36:00)
Continuity mistake: As Hiram is leaving Rejection and is stopped by Fu, his horse changes position from about 1 1/2 feet from the bicycle to the side of the road, about 4-5 feet from the bicycle.
Factual error: In the scene where the people of Rejection/Perfection are preparing to fight the Dirt Dragons, Hereim loads the Punt Gun and puts a little gold piece in it (a percussion cap, containing a small amount of gunpowder used to set off the main charge in the barrel). He shoots at the Dragon when it pops up and misses. The next time he loads the gun, he does not replace the percussion cap (which can only be used once), yet he is still able to fire the gun with no problem and kill the Dirt Dragon.
Factual error: Lu Wan Chang is wearing a denim "jean" skirt with slits in the movie. Though denim or jean pants have been around for 10 years in the movie's setting, jean skirts were not introduced until the 1960s. The fit of the shirt and the slits also would have been inconsistent with modest dress of the women of that time.
