I get this movie has a huge cult following, because i see no other reason why it is so highly rated. Of course, if you are into a young Mel Gibson clad in leather, sweating and bleeding, you will be more than satisfied. If you are into a good storyline or acting you should give chase like one of those you'll see in this movie.
The story kind of continues the first part of the Mad Max series, but on a second look it is only loosely tied into the trilogy, as you will notice some continuity and logical errors when you watch the movies from the beginning until the end. However, since the first part the world or at least Australia went down completely, because some kind of unspecified conflict got the world into a wasteland with marauding gangs of criminals roaming the lands. One of these gangs besieges a Fort that holds one of the last oil refineries, protected by lawful citizens.
At this point, where gas is scarce, you wonder how the gang is able to roam around the refinery 24/7 with their cars, bikes, trikes and whatnot. But this is only one of the many questions you will ask yourself. Another one is how a gang of supposedly brutal individuals follows someone who looks like an almost naked and ridiculous Jason Vorhees on steroids. However, amongst all the other campy elements in this movie you'll hardly notice that.
The only real interesting part are the stunts, especially the car chases. They make up most of this movie and are definitively worth watching.