Nev Pierce at the BBC says
"Lynch ditches a conventional narrative in favour of a seemingly incoherent string of unconnected scenes"
This quote alone just sums up how postmodern the film is. It completely ignores most of the conventional rules in film making, to create a sequence of events that seem fractured as nothing really connects together. At the same time, your never quite sure who's story your following, or whats even going on. This further breaks up the film in such a way that it is impossible to work out the truth to the film. Which really is what postmodernism is all about. What is the truth?
Going back to the BBC review, Pierce describes it as a "surreal, gripping, hallucinogenic trip". Even though the film starts off ordinary enough, there are still some scenes that seem randomly thrown in, but all to disorientate the viewer. Do we even know whether some of the characters are even real or not.
I didn't enjoy the film myself, but that's because I don't like films that don't explain themselves, or have an ending that seems cut short. In saying that, the film couldn't be any longer at 146 min's long! Watching all these individual scenes that don't flow together naturally, made it seem like a marathon! I suppose it's another one of those films that you either like or hate.