Most Disappointing Sequel?

Highlander 2 :(

Highlander 2 was a massive let down, to the point where it never should have been made.

I will agree with the first 2 quotes. Highlander 2 was so bad, that Highlander 3 and the TV series never mention it in the story lines. I still laugh when I think of....THE PLANET ZEIST

I'll say Highlander 2 the Quickening was the worst squel, Highlander was a phenominal movie, and 2 just screwed everthing up about it.

Going to have to disagree with you here. Just because you say something once and then say it again 2 years later does not make it ok :D

Update...ha ha ha.
Wikipedia said
In 1995, Mulcahy made a Director’s Cut version known as Highlander II: The Renegade Version. The film was reconstructed largely from existing material, with certain scenes removed and others added back in, and the entire sequence of events changed. All references to the Immortals being aliens from another planet were eliminated;

I might have to see this.