Plot hole: After the kidnappers kill the trooper and then one chases after the 2 eyewitnesses you can see that they are on a straight road (no turns and he catches up to them fairly quickly) but the next morning when Marge arrives on the scene of the 2 bodies she arrives from the direction of the trooper's body (the first shooting). After examining the bodies of the eyewitnesses she asks her deputy "where the trooper is" and the Deputy points in the direction she just came from and states "down the road a bit" how did she miss it? She would have had to have driven right past the trooper's crime scene to get to the 2 bodies.
Plot hole: When Jerry thinks the investment he has proposed to Wade will work out, he tells Shep he may not need the help of the two kidnappers he put him in touch with. Shep then tells Jerry that he only put him in touch with, and vouched for, one of the kidnappers: Gaear. He makes it very clear that he has never heard of and does not vouch for Carl Showalter. However, at the beginning of the movie, Carl specifically mentioned Shep, saying "Shep didn't tell us much..." etc.) And when Shep is told by Marge that involvement in the kidnapping/murders could put him back in Stillwater, he knows exactly where to find Carl to give him a thorough beating. When he shows up, Carl even recognizes him ("Shep, what the Hell are you doing, I'm banging that girl.") Shep obviously knew Carl, and had no reason to hide it from Jerry, as Gaear was the more dangerous of the two.
Continuity mistake: In the scene when Jean is having a talk with Scotty about his grades and not wanting him to go out for hockey, the phone rings and the camera focuses on Jean and the phone. The microwave clock behind her reads 10:44. Jerry then enters the scene to talk on the phone and the shot reverts to Scotty shouting the obscenity then back to Jerry and the microwave clock now reads 7:43. The shot moves back to Scotty with him shaking his head and then back to Jerry where the microwave clock now reads 11:05. (00:12:35)
Continuity mistake: When Margie is in Jerry's office for the second time and Jerry rushes out to "count the stock", Margie looks at his wife's photo and it seems the photo is just in front of her as she doesn't turn around. When Jerry flees and she stands up, we see the photo is just behind her, under one of the golf player statues. (01:22:50)
Continuity mistake: After the one guy shoots the cop, a blue Ford passes them. So the bad guy goes after them to find that the Ford flipped over. He stops then puts the Oldsmobile in reverse. Just before the car stops you can see that the taillights are from a 1989 or 1990 model. The film is set in 1986 or 1987.
Continuity mistake: The pistol used by Marge to shoot Gaear on the lake changes between camera shots. Look at the length of the barrel as she points the gun at him after he runs off, and then compare it to after she has shot him and points it to the ground. The pistol first seen is a snub nose .38. The second shot shows a "Patrolman" .357 Magnum. (01:29:00)
Continuity mistake: When Margie eats lunch with her husband in the office, the hamburger she holds is alternatively untouched and bitten. This is the most evident when she talks to her colleague about the car. (00:45:48)