Continuity: Alfredo uses a silent Super 8 camera and silent film stock to shoot the movies in his flat, but when we see him watching the results on a projector some days later, the movie has sync sound that was seemingly recorded at the time of the shoot.
Anachronisms: The type of Kodachrome cartridge we see cannot have existed at the time of action: only since the end of the 1990s did European Kodachrome cartridges have their serial number printed on the label with black ink, prior to that the serial number was dry-stamped on the label.