Continuity mistake: In S5:E14 of BB, it shows that Jesse is chained to the roof to teach Todd how to cook. Like if the setup was already there on the same day they kidnapped him. But in El Camino, they show the scene where the Nazis are planning out of the setup for Jesse to cook in and the roof setup is not there yet.
Factual error: In the flash back with Jesse and Walter, they are eating at the Owl Cafe. Outside, a mountain and dirt road can be seen, indicating they are out in some rural area in the desert. The Owl Cafe is actually in Albuquerque and is nowhere near a mountain or desert landscape. It is on one of the busiest streets in the city, surrounded by other businesses such as gas stations, restaurants, and hotels. There is another Owl Cafe in San Antonio, New Mexico, but that one looks nothing like the one in the flashback (it also isn't near a mountain and is surrounded by paved roads).
Revealing mistake: The dead housekeeper's body is moving its hands like it's alive after it's unwrapped out of the carpet.
Deliberate mistake: In the lab where Jessie is working, the canister that Walter had put his bloody hand on when he dies at the end of Breaking Bad still has the bloody handprint on it from that episode. However, this part of the film takes place before that episode happens. In the behind the scenes, the director stated he didn't have the heart to remove the handprint and decided to leave it in as a little "Easter Egg"Quantom X