Plot hole: Necros had absolutely no way of knowing that Bond and Saunders had arranged to meet at the café when they did and wouldn't have had anywhere near enough time to track them down and set up his elaborate booby trap. Saunders only suggested the meeting place and time a few hours earlier, and it was kept strictly between him and Bond. The scene in Tangier, where Whittaker tells Necros to kill another British agent, takes place on the same day Bond arrived in Vienna; meaning that Necros got from Tangier to Vienna (a 5-hour plus flight), tracked down Saunders, acquired the materials to booby trap the café doors (or had planned this ahead of time - unlikely), and set the trap up well in advance of him and Bond getting to the fairground. There was nowhere near enough time for all of that to happen without Necros having psychic knowledge of Saunders' movements.
Continuity mistake: In the last dance scene, Patrick Swayze jumps down from the stage and starts dancing. He goes down on his knees and when he lifts one knee, it is extremely dusty, however when he stands up his knees are completely clean. (01:33:00)
Factual error: Buddy Holly is seen singing 'Cryin', Waitin' Hoping' at the Winter Dance Party. He hadn't actually finished composing this song, never mind recording it as a finished piece of work when he went on his final tour. This song comes from his final recordings 'The Apartment Sessions' which he recorded in New York and was finally released after his death, complete with added backing music and vocals.
Continuity mistake: When he puts the pins in her eyes, evey time it is shown it's different - sometimes they are all covered in blood, sometimes only some of them or one, and sometimes there's no blood at all.
Continuity mistake: After the grocery store visit, Joan Jett walks to her room at the hotel and goes to her room on the second floor, a short time later she opens her room door which is now on the first floor. (01:35:00)