Imagine a David Lynch cake. Blue Velvet is a small slice, a sliver. Lost Highway is a quarter, a good chunky piece. Inland Empire is the entire cake, icing and all. While Lynch's other works feel like your entering his brain, Inland Empire is more like being pushed and suffocated by it, an experience which is both frustrating and fascinating.
It's important to mention how Lynch shot this film, famously on a shitty VHS camera. While in the beginning this looks really terrible, like so bad, this quickly is overcome by Lynch's wonderful surrealism. Once your past the film's halfway point, the grainy, over-exposed footage begins to add to the film's atmosphere. Clearly, Lynch was trying to establish that Inland Empire is supposed to feel like it's a film, you should be able to see all the organs of the film.
The plot? If you thought Lost Highway was confusing, get ready... This film is incomparable. I suppose some may think Eraserhead gets close. I suppose in Eraserheads untraditional narrative, yes. But, Eraserhead is a lot more clearcut than Inland Empire. Eraserhead is quite clearly about parenthood and responsibility. Inland Empire has similar themes to Mulholland Drive but with some elements which are so disparate. Namely, the rabbit sitcom and the polish setting. While it's frustrating to watch, you cannot help but be enticed by Inland Empire which is undoubtedly a deeply personal piece of Lynch himself.