In a DEA briefing, Hank mentions that "nine illegals plus the driver" had been murdered in the burnt-up truck that was being used to smuggle illegal immigrants. However, in No Más (2010), there are twelve passengers in the rear of the truck, including the Salamanca brothers. So there should be ten illegals plus the driver dead.
Before the cop car pulls behind Walt's car, there is no car seen on the road behind him in the long shot, but when looking through the windshield at Walt, there's a car behind him.
The pizza that Walter throws up to the roof is a different one than that the one in the next shot (close up) from the roof. The first pizza has a few big visible slices of pepperoni sausage on it, while the pizza in the close up consists of many little slices. Also, in the first shot there are five rows of tiles between the pizza and the lower end of the roof. In the closeup there are only three rows.
At 38:30 Ehrmantraut parks his car in the road facing the White's house. The car is seen again in the background in the road at 39:50 as Walt is unpacking his vehicle. But at 40:40 when Walt is seen walking around the house and through the gate, the car is not in the road. When Ehrmantraut returns to the car at 42:00, it's back in the road.
When Walt gets pulled over, the view from the camera through the windshield shows it's perfectly intact. When the cop walks up, the windshield is shattered.
The pizza that Walt throws on the roof is one whole, uncut pizza, which is unusual. However, in season 4's ep 2 "Thirty-eight Snub" Jesse orders several pizzas that are delivered to his house, and Badger explains, "That's the gimmick. They don't cut their pizzas and pass the savings on to you!"
When the cousins are using the Ouija board to get Walter's name from Tuco's uncle, the one pointing at the board is holding it at such an angle that the other couldn't possibly see which letters he's indicating.
When the police car is shown in Walt's rearview mirror, the police car's flashing lights are lower than Walt's eye line, revealing that Walter's car is in a "picture car" for the shot and is above normal level.
When the Salamanca cousins sit on Walt's bed, their chrome-plated ax clearly has a dulled blade.
When the Salamanca brothers are sitting on the bed, a closeup of the chromed axe shows that the blade has not been ground and sharpened to a cutting edge. Would still be a nasty weapon though.