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).

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.

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.

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.