Goof (errors in geography): The episode "Hook Man" is set in Iowa. Yet in an overhead view as they pull into town, you see palm trees.
Goof (factual errors): In every episode (through episode 2.20), the boys are showing off a Kansas license plate, the county tag reads "SG". In all actuality, the county for Lawrence should read "DG" for Douglas County.
Goof (continuity error): In the scene where Dean gets arrested his coat collar jumps up and down.
Goof (factual errors): Fire Engines in Lawrence, Kansas during the 1980s were painted lime green, not red.
Goof (continuity error): When Sam is shuffling through Dean's cassette tapes, he picks up a Metallica cassette and Dean puts it in, but an AD/DC song plays instead.
Goof (errors in geography): They say this episode takes place in the area around Grand Junction, but the problem is that the geography of that area is all desert, not full of trees like they implied in the episode.
Goof (factual errors): It is stated several times that Grizzly Bears are the cause of several deaths in the area (in Colorado), and a picture of a large dead bear is shown in the Ranger's office. Grizzly Bears are not indigenous to Colorado, only American Black Bears are; a smaller, less vicious species of bear.
Goof (continuity error): In the beginning, when Tommy is filming his message to Hailey, his dialogue says: "Hey, Hailey. Day 6. We're still out near Blackwater Ridge. We're fine, keeping safe, so don't worry. Talk to you tomorrow." But when Hailey plays the recording for Dean and Sam, the message becomes: "Hey, Hailey. Day 6. We're still out near Blackwater Ridge. We're fine, keeping safe, so don't worry, okay? Talk to you tomorrow."
Goof (errors in geography): There is no "Black Water Ridge" in the Lost Creek wilderness of Colorado. The coordinates left by their father (35, 111) actually meet in Arizona.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): When Sam and Dean first introduce themselves to Hailey, Dean says his name is Dean but the name on his ID says Samuel Cole.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): Upon arriving in Colorado, while the Winchester brothers are at the ranger station gathering information, Sam states that they are natural resource majors at UC-Boulder. The school is actually known as CU-Boulder.
Goof (continuity error): When Dean is introducing Sam and himself to Hailey, he says, "I'm Dean, and this is Sam." However, when she asks for ID, Dean shows her an ID with his photo and his name being Samuel Cole.
Goof (factual errors): The brothers use Anasazi symbols to fight the Wendigo in Colorado when the tribes were actually located in the Southwest. Dean says that Wendigo are typically found in the Northeast of the country (Minnesota) and he's never heard of one as far west as Colorado.
Goof (continuity error): When we first see Dean, he is circling the girl's picture in the newspaper. When he shows the paper to Sam, the circle is different. He originally circled her name as well, but it wasn't circled on the paper Sam had.
Goof (continuity error): When Andrea gets to her bath the level of water rises as expected, but as soon as the "green water" pours into the bath, you can see that the level of water has decreased.
Goof (continuity error): In the scene where Bill's son is about to be drowned, he attempts to pull the plug out of the blocked sink. However, if you look on the board to his left, the plug is already on the side, just before he pulls it out of the sink and puts it in the same place.
Goof (revealing mistake): When Sam rescues Andrea in the bathroom you can see she wears panties in the left side of the screen.
Goof (continuity error): When Will Carlton is chopping potatoes for dinner, the sink plug is on the counter. When the sink begins to fill, the plug is in the drain.
Goof (errors in geography): There is no "Lake Manitoc" in Wisconsin.
Goof (boom mic visible): At 5:11 a boom mic pops in at the top center while Will gives his line.
Goof (crew or equipment visible): (at around 51 mins) There is a mic cable visible on Sam as he is talking with Andria.
Goof (revealing mistake): As Sam and Dean are driving to the church Sam's face is reflected in the window behind him. It should be the back of his head.
Goof (continuity error): When Mr. Carlton's son reaches into the sink to pull out the plug, the plug is sitting on the counter next to him. He then proceeds to pull it out of the sink and set it on the counter.
Goof (factual errors): While the Winchester brothers hail from Lawrence Ks, which is in Douglas county, the plates on their car are registered in Sedgwick county, nearly three hours away.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): At the beginning, the man who is possessed is sitting several rows and on the other side of scared guy. Then scared guy at the mental hospital says "he was a passenger, he was sitting right in front of me".
Goof (audio/visual unsynchronized): When the stewardess talks to the pilot at the beginning, her lip movements don't match the words that come out of her mouth.
Goof (continuity error): The light aircraft which crash is shown before take off with square windows and the registration C-GBBP, and then in flight it has round windows and the registration C-GUTY.
Goof (revealing mistake): (at around 21 mins) The reflection of Charlie in the glass is wrong. The reflection is of her right side, it should be of her left, the side that actually faces the glass.
Goof (continuity error): During the last fight between Sam and the Skinwalker at Rebecca's place, the Skinwalker puts a knife on the pool table. When Sam flips up to cut his hands free, we see that he has bound feet. In the next shot, his feet are free already, without him ever having a chance to use the knife to cut the rope.
Goof (continuity error): Towards the end of the episode, right after Sam cuts the rope binding his hand and kicks the shape shifter "Dean", Sam wields the knife. "Dean" grabs his arm and flips him upside down and the knife disappears: it's no longer in Sam's hand and not on the floor.