The 1954 calendar is wrong. All the days are out by one. The calendar shows that 1st April, 1954 is a Friday. In fact it was a Thursday.
When Toto is young, the films that Alfredo gave him catch fire. They burn and ruin the only picture that his mother had of his father. When Toto is a grown up, this "burnt" picture is hanged on the wall totally unharmed.
When Toto and Alfredo is taking the test at school, there are supervisors walking in the background. They repeatedly "jump" around between shots.
Toto as a child is shown to be left-handed during the school examination sequence, but as a young man he is right-handed as he marks off the days on the calendar. In addition, when in the army, he fires the rifle right-handed.
In one scene, scenes from the film ...And God Created Woman are shown. Several scenes later, Salvatore is shown marking a calendar dated 1954. "And God Created Woman" was released in 1956.
The projection room of the Cinema Paradiso seems to have only a single projector. In those times theaters had at least two projectors and the film was mounted on multiple reels. It was the projectionists job to switch projectors seamlessly.
When the subtitles are shown for the film "Seven Brides for Seven Brothers" it reads "Unforgivable songs" rather than "Unforgettable songs"
When Toto is a kid, and he and Alfredo are writing the exam, Toto throws a ball of paper to Alfredo. In one frame, he is throwing it with his left hand and in another frame he is throwing with his right hand.
When grown up Toto looks at the photos on the wall in his former room you see that Alfredo and young Toto are cut out and glued to the picture of the Paradiso.
When Toto leaves Giancaldo on the train a man with eighties costume, purple shirt and two baggage, is clearly visible.
When the (adolescent) Salvatore is leaving home on the train, we see Alfredo getting up out of the seat on the platform. The next time we see him, he's seated again, and getting up again.
When Toto is caught by his mother outside the theater, the man who picks out a can of tobacco from his left pocket of his pants in shown to put his right hand in his right pocket first.
When the film is borrowed from a neighboring theater, we see that the projector is apparently located in the balcony of the theater, not in an enclosed projection room. Furthermore, the projector has a "magnetic penthouse" sound pickup, an attachment used to play early stereophonic prints. This process would not be invented until 1953 and not used widely until years after nitrate film was phased out.
When Toto runs to rescue Alfredo from the fire he falls face down, but in the next shot he raises face up.
Before the theater is demolished, we see barricades in the parking lot. The camera pulls back to show the crowd watching even further back from a safe distance. Once the explosives go off, two firemen suddenly appear standing just behind the barricades.
When Toto and Alfredo are taking the test at school, Alfredo acquires an ink smudge on his right cheek. During the test the smudge changes shape and intensity several times.
While Toto is in the Italian army, he is shown with a close-cropped military haircut. After he is discharged and returns home, his hair is suddenly long again. That's because he spent a year in the military; more than enough time for his hair to grow back.
The heights of Toto and his mother change dramatically during the course of their adult lives. Jacques Perrin is much taller than Marco Leonardi and Pupella Maggio is much shorter than Antonella Attili. As a child and teenager, Toto is clearly below average height. In middle age, he is the tallest man at Alfredo's funeral by a clear head.
When Toto is marking the December 1954 calendar in order to check out the day until December 31 to see if Elena Mendola accepts him as a boyfriend,the actor who plays young Toto [Marco Leonardi] is clearly left handed, but when he checks out the days left on the calendar, we see that a right-handed guy [obviously not Marco Leonardi] writes down on it.