The unmade script for the sequel to “Buckaroo Banzai Across the Eighth Dimension,” called “Buckaroo Banzai Against the World Crime League,” is just a google search away. It’s online in a bunch of places, check it out.
To say the tone is different from the first film is an understatement. If Against the World Crime League came out when it was supposed to, it would have been incredibly ahead of its time. The only thing I can compare it to is Sam Raimi’s films like Army of Darkness, which has a tone of being horrific, but things are so surreal it’s almost darkly funny. An example would be that Hanoi Xan tries to kill Penny by hanging her by her own hair. Gruesome, but so weird you have to laugh a little.
One character in the script is Pecos, only mentioned in the first film. Among other things, we discover that Pecos is a woman, and we find out that the reason we don’t see her is that she’s investigating rumors of Hanoi Xan’s return in Asia.
By the way, there is no truth to the rumor that Big Trouble in Little China started off as Buckaroo Banzai Against the World Crime League but was rewritten.
There is, however, truth to the rumor that Christopher Lloyd got the part of Doc Brown in Back to the Future because of Buckaroo Banzai. His co-star John Lithgow was the original choice for Doc Brown, but he was unavailable and suggested his Buckaroo Banzai co-star and fellow Red Lectroid Christopher Lloyd.