Weird? Yes. Unusual? Campy? Nutso? Yes on all counts. But major chunks of plot are evidently left to the telepathic abilities of the audience, and performances are either wooden or seriously over-the-top. John Lithgow is the saving grace of this film, and his role is totally insane.
From a cinematic and production viewpoint, this is not top-shelf. From a story line viewpoint, it's silly. Not that there's anything wrong with silly... if it's good silly. But this is camp that intends to be camp and fails. It's humor that sometimes kinda works but usually doesn't. It has one truly memorable line... and even in that "Monkey boy" just isn't all that funny. I'm sure some folks find it hysterical. Hey, to each his own, monkey boy.
There are many, many viewers who consider themselves some sort of elite group because they "get" this film and if you don't agree, you're just clueless. The truth is some people are going to love this... and a whole lot more won't even bother writing a rewiew. I love campy films, and sci fi camp more than anything-- if it's well done. This isn't well-done camp. The supposed "secret references" are often figments of viewer imagination. The directing is disjointed and inconclusive. Overall it just sort of hits the end and... ends.
I really don't know why this became a cult classic. There's no denying that it did, nor that many people absolutely breathe this film. That doesn't mean viewers *have* to love it... or that anyone is stupid in declaring it "not the best movie ever made"-- because it really isn't (not by a long shot).
If someone loves this film... good on ya and more power to you. That doesn't mean that people who dislike this film are idiots. It means they demand a bit more in cinematic experience than "let's throw stuff at the screen and see what sticks". This *could* have been a great film. With a bit better script, a bit less cocky directing, and a bit more story this could have been an all-time great. Unfortunately it falls significantly short of that. Be a starry-eyed fanboy all one wants, this one needed a bit more polish.
Some people think a man running around in a rubber Godzilla suit is the height of movie history. Other people... not so much. Doesn't mean that either one is wrong. It means that Buckaroo Banzai may prove to be an acquired taste... or one that is unpalatable.