Continuity mistake: When Hank/Charlie fall into the car near the end his feet are inside the car. When the shot changes his feet are on the outside.
Character mistake: When Charlie leaves with Irene, the woman asks "but Captain, policework is Charlie's..." The man she is talking to is a Colonel.
Character mistake: Shonte Jr. says he can't figure out of the atomic mass of a deuteron. He is supposedly a genius, but this is chemistry 101. Average people might not know how to calculate atomic mass, but a genius would not make a beginning level error like this.
Continuity mistake: When Charlie is choking the cow the sun changes between shots.
Continuity mistake: While Hank is driving the red mustang and takes Charlie outside, the car the sun changes between shots.
Continuity mistake: At the restaurant when Charlie yells to the kid with the milkshake, the child drops it and makes a puddle besides their table. In a few shots later the amount of milk increases and moves away from the table.
Continuity mistake: When Irene goes to leave the diner after Hank's jokes, his cigarette switches from his left hand, to his right, to his left again.
Continuity mistake: When Charlie and Irene meet with Gerke, Gerke hides his gun under his arm.He then moves his arm to his side but then in the next shot it's back under his arm.
Factual error: Much of this movie was filmed in the Burlington and Middlebury areas in Vermont. Therefore, there are a lot of inconsistencies with vehicle plates and identifying characteristics of things like particular state trooper uniforms/cars/etc. And yes, the abandoned bridge/railroad trestle/etc. is actually the pedestrian bridge over the Otter Creek in downtown Middlebury.
Continuity mistake: Just notice that in the clip at the very, very end of the movie, when Whitey says he thinks he's found the missing thumb, he ducks under without the hose in his mouth. But in the water, it's in. Then when he comes back out, it's out again!
Revealing mistake: When Irene trips by the cliff she just kicks the floor and twists her ankle.
Visible crew/equipment: When Charlie starts beating the mirror on the train you can see the boom mic on the right of the reflection.
Revealing mistake: When Hank crashes the car through the shop, look at the barber's chair. You can see it's a stunt double for the actor.
Continuity mistake: After Hank has conned Irene into sleeping with him, the morning after Irene finds the "Coke" machine smashed up. In a later scene the Coke machine is back in perfect condition.
Character mistake: Throughout the movie, Carrey's Commanding Officer, who is a Colonel, is called Captain.
Continuity mistake: The bandage on Jim Carrey's chin changes size frequently throughout the movie.
Chosen answer: If you watch until after the end credits, you see it get eaten by a fish.
J I Cohen