(at around 56 mins) When Odd borrows Rosalia's car, the license plate is 1ITA340. When he leaves Fungus Bob's house after the explosion, the license plate is 2SAI222.
During the shooting scene, the neon sign in the ice cream store alternates between being shot out and being back on.
In some scenes, Stormy's nametag says MANAGER on it, in others it doesn't.
When Stormy and Odd are sitting in the mall, eating ice cream, there is a drip on her cone that is almost to her finger, but disappears in the next shot.
When Stormy enters the diner, she opens the door twice.
Bodach, the name of the phase-shifting misery leeches, means "old man" in Gaelic and is pronounced "buh-DAHCH", where the ch is a guttural crash. An English speaker might prefer to replace the crash with a k sound, but the "BO-dack" pronunciation consistently used in the film bears no resemblance to the actual word.
The first listing on Fungus Bob's browser history is for "Church of Satan". This organization abhors violence except in self defense, and is comprised almost entirely of atheists.
When Odd takes the gun from Eckles to shoot Kevin Goss near the ice cream shop, there are four rounds in the clip. He never cocks the gun, which would have put one of the four rounds in the chamber, but it locks open when he fires the fourth round. The only way it would have fired without cocking it is if there was a fifth round which would have been in the chamber. However, that would mean that the gun wouldn't have locked open once the fourth round was fired.
The holes in the wall of the ice cream shop are far too large to have been caused by an AR-15.
When the chief's wife pulls Odd's chain from around his neck at the hospital, it is visible for a slight second as a pair of dog tags and then as a heart when she shows it to Odd. However, the chain actually has two dog tags and the iron heart pendant. When the wife focuses the pendant to show Odd, the dog tags are hanging off/below camera.
Following the explosion of the van, you see the fire follow the man-made riverbed. In the lower left corner a CGI version of Odd Thomas' car comes to a stop then turns hard. This is not Odd's car (or, rather, Rosalia's), but that of someone following the van.
When Odd and Stormy are riding the scooter after leaving Viola's kids, they ride past a car dealership. All of the signs at the dealership (including the sign out front) are backwards, except for the large "Quality" sign in the middle. The film was reversed to change their direction of travel, but only one sign was fixed.
When Odd Thomas leaves the mall in the step van, he side swipes a car. In subsequent scenes with the van, no damage is evident on the side of the van.
Thomas says that he was originally supposed to have been named "Todd, after a Czechoslovakian uncle". Not only is he referring to a country which had not existed for over two decades, but also to an Anglo-Saxon name - "Todd" - which exists in neither Czech Republic, nor in Slovakia.
The ending shows Odd walking through the desert and approaching Las Vegas on foot; however, if he walked from California, he would be approaching from the West, but the view of Las Vegas he sees is that of approaching from the East, judging from the arrangement of the casino hotels on the Las Vegas Strip.