When Jesse is introduced to Don Eladio as the new cook, the punch mark on Jesse's face changes from the shape of letter "B" to "O" and then back to "B".
Gustavo, Mike and Jesse are waiting to be introduced to Don Eladio. As Don Eladio approaches, Mike tells Jesse to stand up. Jesse is walking from the table towards the side of the pool. In the next shot, we see Don Eladio walking up towards the group and we see Jesse again walking from the table towards the side of the pool.
Walter talks to his son Walter Jr. about his father who had Huntington's disease. This is a genetically transmitted serious neurological disorder that manifests itself in half of the offspring. He tells his son that as a kid (his father dies when he was 6 years old) he had "all sorts of tests" and was declared OK. This must have been in the sixties when there was no test available. Even in the earliest stage well into adulthood even meticulous neurological examination was often inconclusive. In a kid it would be impossible to state whether it would get the disease later on in life. The first genetic test came available in 1993 when a "Huntington-gene" was discovered.
When Jesse is making meth in Mexico, one of the cartel members records the process, and we see the camcorder screen. It says "HDV" in the upper left. That is a tape format, the longest tapes hold 80 minutes maximum, yet the remaining time on the same screen is over six hours in the first scene (and over seven in the next).
The registration of the Kodiak 100 used to fly the crew down to Mexico, XA-8AC, is not in the proper format for a Mexican registered aircraft. Mexican aircraft registration consists only in letters, with the ones beginning with XA being assigned to aircraft registered to companies, as opposed to private individuals which would be assigned a registration code beginning with XB.