But "opaque" and "impenetrable" are good words. "Frustrating" would be another. I tried to read Joyce's A Portrait of the Artist as a Young Man, when I was young myself. I got what was going on, but at that time, I didn't see the point of it all. Today, I see what Joyce was after, but the it doesn't seem worthwhile to reread the book. Ditto for Proust. He's not that unclear, it's just that his method of approaching his story can be maddening.
More recently, I tried to read Toni Morrison: Beloved, among others. I had trouble figuring out what was going on, and why it was supposed to matter. Ditto for Arundhati Roy's The God of Small Things. And Virginia Woolf's The Years. Woolf's vision of what a novel could be has some value, but she doesn't really live up to her ideal. Her real talent was as an essayist.
Once you've left school behind for some years the whole Joyce-Faulkner project of writing books that are only accessible with expert decryption comes to look questionable, if not misguided. It might have worked for Joyce himself, but three generations on the game starts to lose its excitement.
Now there's the rub. Games are always funner when you know the rules.