Not sure how well this will go down but it's something I find ineteresting and I've actually discussed with friends. Defining movies according to a musical style.
Question; What is a Prog Rock/Metal movie?
Here's my assertion; whether it is a popular movie or not it can
1.) go against popular convention
2.) have many layers to the storyline
3.) be Epic in it's scope
4.) use metaphores in conjuction with the movie's concept
5.) use an analogy in conjuction with the movie's concept
Obviously, the above is just a starting point. There's many other points or descriptions that can go with the above.
Also, a movie doesn't have to be just one thing, it can be a combination of different things. Eg. Pan's Labyrinth is both a Fantasy as well as a Drama and uses metaphores and analogies in it's storyline and concept. It could be described as a Progressive/Power Metal movie.
What wouldn't be a Progressive Rock/Metal movie? One that doesn't ascribe to the above description, whether it's a great movie or run of the mill, it's one that doesn't deviate from the norm and doesn't challenge the viewer's intellect any huge way. Eg. Action Jackson or most movies with Steven Seagal, Van Damn etc. (I actually like some of those films and some are actually great Action films but you get the picture). Action Jackson, I could describe as a bit of old school Thrash and Sleaze Rock Movie; get's the heart pumping, a bit cheesy and over the top, full of adrenaline.
Also, with other forms of music, other forms of art mix together and influence each other. E.g. Baroque music had parallels with the art and architecture of its time and they influenced each other etc. Film has influenced music and vice versa, e.g. I think it's fair to say that Avant Guard film and Art has had an influence on Avant Guard music etc. Also, I think that the movie "Dead Again" was a huge influence on "Scenes From A Memory", that could also be something discussed here.