When the jeep pulls off the road after almost hitting the guy with the pumpkins, the passenger side mirror is up in one scene, then down then next, and back and forth several times. Furthermore, when they arrive at the pumpkin patch in the next scene, they're driving in a completely different make and model jeep. Then again in the last scene, they are in still another, a *third* jeep, this time with an enclosed back section.
As the party begins, the camera reveals the party band and clearly shows the "Austin Powers" kid and the blond Charlie's Angel dancing to the music; however, immediately afterward, the camera pans to the van outside, where the same characters are making out.
During the movie the white Jeep Wrangler that they drive changes.
When Jonathan and Tammy are getting to know one another, the weather switches between calm and breezy, sunny and overcast, frequently.
When the brother is unloading the jeep , he asks the sister, "What about the top?" meaning that he wanted to put the top on the Jeep. At the end of the movie, Jeep number 3 has a hard top, not a convertible top. There would have been no way to transport the top of the Jeep .
When blond Charlie's Angel has her head trapped in the rear window, being "karved", you can clearly see her face as a different color than the make-up and latex containing the blood packets.
In the first kill scene you can tell it's in the garage not a basement, the garage door is visible and the deadbolt on the door to the house is a giveaway with the key on the garage side for whatever reason, oil or paint stains on the floor and boxes piled up, then the brother walks directly from the dining room to the garage and mistakenly kills his sisters masked boyfriend. The news announces it took place in the basement.
At one point, Lynn mentions to Tammy that she hadn't seen Jonathan since his fight with Lance. However, prior to this scene, Tammy was seated right next to Jonathan and a few other party guests during the drinking game scene.