I'm a big David Lynch fan and while watching Twin Peaks FireWalk With Me, I realized that a viewer doesnt have to be familiar with the TV show for the film to work.
When removed from the context of the TV show the film works as a dreamier, more impressionistic companion to Blue Velvet--about how small towns can harbor big evil, and about how damaged people can damage others in their orbits.
Of course, that's not entirely what either film is about, but I think the commonality connects Fire Walk to the Lynch film ouvre in a way the series, at least the first two seasons, doesnt.
In a way, this connection makes Fire Walk more and better than just about any other prequel. It doesnt need the thing it's prequeling. It can stand on its own.