Plot hole: Preparing to steal methylamine from the train, Walt, Jesse and Mike measure off a predetermined distance from the railroad crossing, which happens to coincide with a handy arroyo, where they bury their tanks. Problem is that they couldn't have known that distance (calculated by knowing the position of the methylamine tanker car in the train) until Lydia told them. But she didn't call that info in until the night after they'd already buried the tanks.
Continuity mistake: A little boy finds a tarantula at the start of the episode and picks it up, letting it crawl over his hands. In the overhead shot of his hands, it shows him letting it crawl up his left wrist and start to get on his sleeve. But in the next shot from in front, suddenly the spider is in the middle of both his hands crawling over them.