When Molly hears the tape recording of Lester Nygaard's phone call to Lorne Malvo from the previous year, there is a difference from the initial phone call. In the first call, there was a long delay before Lorne replied to Lester begging him to come.
When Lester tries to order a beer at Lou's, Lou tells him "Sorry, family place". However in an earlier episode beer can be seen on the menu board hanging on the wall behind the counter.
When Lester is running on the ice, it can be seen cracking behind him. In the next wide shot from overhead, there is no crack in the ice.
Mistaken observation. The next overhead shot is at 58:16 and cracks can be seen front and behind. When ice breaks up, there's more than one crack.
Mistaken observation. The next overhead shot is at 58:16 and cracks can be seen front and behind. When ice breaks up, there's more than one crack.
There is a cabinet from the Ikea Trendig 2013 collection in Lester's new house, whereas this takes place in 2007.
When panning overhead at the used car dealership, a fifth-generation Ford Explorer is shown in the upper left corner of the lot. This vehicle was released three years after the show was set.
When the police enter Nygaard's insurance shop after Linda's murder, the filming set is visible whenever the camera looks up. Also, the area inside is far bigger than the shop's dimensions from the outside.
Lester successfully fends off Malvo's attack by setting up a booby trap with a spring trap. The result of Malvo's stepping into that trap was a seriously injured leg. Later, after Malvo has managed to get back to his cabin, the viewer can see that the nature of the injury was a compound fracture of the tibia, with the bone actually sticking out of the skin. Yet Malvo was able to walk out of Lester's bedroom, go down the stairs, out of the house, and to a car (which he used to get back to his cabin). Then Malvo was able to get out of the car, go to his cabin, and to his couch. That is a lot of walking on a limb that could NOT have possibly supported his weight. With the bone sticking out, he would have gone down before he got to the stairs in Lester's house. AND he would have NOT gotten back up. The two pieces of bone would have bypassed each other when he put any weight on them, and down he would have gone rendering his leg completely inoperable and useless. But if Malvo could not have overcome such an impossibility and gotten back to his cabin, then Gus could not have corrected his earlier grave mistake and slayed his demon.