Factual error: In the newspaper article from the Trinity killers past - the report states that someone called 911 and dispatch gave them instructions. The death occurred in 1959. The first 911 call was made in 1968. (00:39:24)
Continuity mistake: Episode: "Man Hunt": When Jonas tries to interrogate the hardware store owner, the owner falls off his chair, knocking it over. In the next shot it's standing upright again.
Continuity mistake: When the bad guys create a roadblock with their 2 cars as Hopper drives his girlfriend to her mother's house, the cars stop with one on one side of the yellow line, and the other stops with the steering wheel over the line. The camera angle changes, and now both cars are neatly, evenly positioned, with their engines sitting over the line. (00:02:05)