The plot takes place in early '70s. In one of the first cuts, when Nacho is a kid (some 20 years before the main plot), he pulls off a cloth from above a color TV. Color television started in Mexico in late '60s.
When Nacho's habit catches fire in church, the leggings on his costume are obviously blackened with soot as he rolls on the grass outside the church. When he stands up, the leggings are only slightly soiled. Also, he is wearing his Lucha Libre red boots and not the white boots he had been wearing right before the fire.
In the opening when they show young Nacho gathering items to make his first cape, the hand/fingers that reaches up to grab the rosary beads is thin and then when it shows him assembling the cape the hand/fingers are chubby.
At the end of the party scene, Candidia grabs Esqueleto legs and tries to pull him into the tunnel, you see that the plant gets knocked down. A few seconds later the plant gets stood back up, but by the end of the scene the plant is back knocked over.
Nacho tosses a handful of chips into the alley to entice Stephen to come out. The tossing would likely spread the chips all over the alley. When Stephen is eating the chips they are in a nice little pile.
When Nacho set the trap for Stephen in the alley, when viewed from behind Stephen has his left elbow between his knees. Change camera view from the front. Stephen has his left arm wrapped around the outside of his leg. From behind, his right arm is above his knee. From the front, his right arm is wrapped around the outside of his leg.
After their first match, Ignacio shows Steven a design for his Nacho costume. Steven is covered in bee welts and moaning in pain from having the beehive thrown at him, this scene was apparently supposed to take place directly afterward.
When Nacho and Esqueleto are presented for the public in the first fight, the host says in Spanish: "esQUEleto", with "stress" over QUE, but in Spanish the word is pronounced "esque LE to", the tonic is the LE, not QUE.
At the beginning of the first match, Nacho and Esqueleto are asked if they want to do a mask or hair match. Nacho says they will bet Esqueleto's hair. Since they lost the match, Esqueleto should have shaved his head.
When "Chancho" and the orphans first start watching Nacho on television they are wearing their day clothes. After the shot of "Chancho" covering the TV, the orphans are all wearing their pajamas i.e white tank tops.
During the fight sequence between Ramses and Nacho towards the end of the movie, Nacho is knocked down and Ramses pulls him back up by his hair. Ramses then punches him once or twice, and then goes to knee him in the face. When he does this, you can see that Ramses knee never makes contact with Nacho's. It is actually several inches away.
Silencio would have been disqualified from the Battle Jam in real life as he used the tombstone pile-driver on Nacho, which is illegal in Lucha Libre. Indeed, the movie fails repeatedly to follow the rules of Lucha Libre.
The winner of the Battle Jam will win $10,000 Pecos, and the right to fight Ramses in an exhibition. Silencio won the Battle Jam, so he won the money. Nacho did not win any money for beating Ramses as the participants of an exhibition are never paid.