Nicole cuts her arms several times through the movie, yet when you see the insides of her arms in other scenes, most of the time she doesn't have a scratch on her and other times she has a really horrible gash in a place where she wasn't cut before.
(at around 6 mins) In Nicole and Jess's love scene, while she's filming him, you can see he's got a patch of hair in the middle of his chest, but in all of the close-up shots of their chests, the guy's chest is completely shaved.
The late 1970s Ford F-Series pick-up truck that has been chasing Nicole through the whole movie changes at the end in the final showdown right before it catches fire. You can tell that it changes from a late 1970s model to a 1969 model year after it blows up and is on fire. They shared a similar body styles but different grilles and front ends.
(at around 8 mins) When Nicole and Jess are driving, before nearly wrecking into the truck, you can see a camper in her side mirror. Then, in all of the scenes when it switches back to her, the mirror is facing down towards the ground.
The Chrysler Lebaron Convertible that Jess and Nicole are riding in can't decide if its headlight covers should be up or down between scenes. One time they are up then down then up and then down then up and all this during the daytime without the headlights being on.
(at around 39 mins) When Nicole meets Tracy Kress in the bathroom, Tracy tells her she wanted to see the Stones play in Tucson. Later Nicole finds out that Tracy went missing in 1971. The Rolling Stones didn't play in Tucson, Arizona until June 14th, 1972.
After Nicole and Jess drive away from the house at the beginning of the picture and are shown driving on the highway, they pass under a sign that says "Soledad Highway exit", which means that they're driving on the Antelope Valley Freeway (CA State Rt. 14), north of Los Angeles. But shortly afterwards they pass another sign on the side of the road that says "Welcome to California", implying that they've just crossed the border into California, when in reality at that point they would have already been in California for quite some time.
As the truck drives towards the rest stop at the very end of the film, to the side of the road you can clearly see a small white house, to which at any time she could have escaped to.
(at around 45 mins) When Nicole sees Tracy Kress Poster it says that Tracy ''disappeared'' in 1971 but in Rest Stop: Don't Look Back (2008) we see the truck driver being killed off in 1972 so Tracy could not have been killed by the truck driver unless he was still a human.