Highlander II: The Quickening (1991)

Continuity mistake: During the big fight scene near the end, the baddie manages to drop the hero down an elevator shaft in a warehouse. The scene ends with a shot looking up the shaft at the bad guy laughing demonically, looking pretty mucky and with hair all over the place. Cut to the next scene where the bad guy appears in a room where the shield beam is generated. Now he is completely clean, has a different hairstyle, and if I remember right has a completely different costume on. (This is because the final fight is actually a combination of two separate scenes - the scene in the elevator shaft was originally meant to come halfway into the film, but the scenes around it were cut, so it was added into the final battle. It has been restored to its original place in the "Renegade" cut of the film, but this mistake is still present in the theatrical version).

Continuity mistake: Near the end of the movie, Katana and Blake are worrying about the possibility that MacLeod has spoken with Neyman and knows the exact coordinates of the hole in the shield. That's odd, because a few scenes before we see Katana and Blake monitoring MacLeod as he speaks with Neyman in the prison Max. There Neyman tells the coordinates. So they know he knows.

Revealing mistake: At the beginning, when all the guys are running away from the explosions in the war, you see a guy getting thrown into the air, but the black kickplate that propels him into the air is clearly visible.

Trivia: This film's plot (ret-conning in an extra-terrestrial origin for the immortals) was so notoriously hated among fans of the original film, it was completely disregarded in subsequent sequels, and an alternate cut of this film (removing all alien references) was later released to appease fans.

Trivia: The producers didn't want to make a sequel to the original, but were pressed to do so by foreign investors due to the original being a hot-seller on VHS. During production, filming became a nightmare, as the script was constantly being re-written to contrive different ways to continue the story, and the film went over budget, causing the insurance companies involved to take over production and further "mess with" the storyline and effects to get it done quickly and cheaply. Director Russell Mulcahy was so ashamed of the finished film, he walked out of the premier before the end of the first act, and co-stars Christopher Lambert, Sean Connery and Michael Ironside have all admitted that the film was absolutely terrible. Lambert only finished filming because he was contractually obligated to the sequel, whereas Connery only made the film due to his friendship with Lambert and the steep paycheck he received, which he wanted to donate to charities he supported.

TedStixon

Trivia: The original script had a cameo from "The Kurgan", the villain of the original. It was going to be revealed that Kitana had paid him off to go to Earth and kill MacLeod. Kurgan's death would be part of what eventually motivated Kitana to send his other goons after MacLeod.

TedStixon

Juan Ramirez: You've remembered almost everything I taught you.
Conner MacLeod: I've had a lot of practice lately.
Juan Ramirez: There is no substitute for experience.
Conner MacLeod: What experience? You've been dead for five hundred years.

Katana: The remains of your mortal wife. So frail. So earthy. So very dead.
Conner MacLeod: At least she's at peace.
Katana: Peace is highly overrated.
Conner MacLeod: Things don't change, Katana, I like that. After all these years, you're still a jerk.

Ramirez: Most people have a full measure of life... and most people just watch it slowly drip away. But if you can summon it all up... at one time... in one place... you can accomplish something... glorious.

Question: Can anyone give a reason as to why he was made younger after being hit with that gas tanker with the lips? It's true that he was once again immortal, but that doesn't mean that he should've reverted to the age he was in the first film.