It was a really good P.S to the story. Felt more like a Western than BB ever did. IT didn't really change anything from the show...didn't hit us with a "guy behind the guy behind the guy" who was going to be a antagonist for Jesse in the movie. The cameos weren't extraneous. They were organic to the story. The flashbacks were decent......with the Walter/Jesse being pretty interesting as it was probably the last time Jesse could have gotten out (after that, Combo gets killed, they get involved with Gus, Jane dies and he's on his path) and that Walter was Walter White and not Heisenberg ( after it...Walter goes in remission, gets tired of retiring and decides to become full on outlaw).
If they had released this in theatres or made a HUGE deal about it....I could see it disappointing. As it was delivered.....it was cool.*
* Although I think if they went totally incognito with it and released El Camino with a no fanfare....it would have gotten more street cred pop.