“How Green Was My Valley” is still a very good movie — just not as good as “Citizen Kane.” Both movies are ambitious with epic scope, but “Kane” was more experimental. It was Welles’s first movie (he was schooled in the art of camerawork on the job by cinematographer Gregg Toland). His inexperience wound up being a surprising benefit: “I didn’t know that there were things you couldn’t do, so anything I could think up in my dreams, I attempted to photograph,” Welles recalled.
“Citizen Kane” is a movie that always moves, whether the camera tilts/pans/zooms within a frame or in the lickety-split editing. (Take the breakfast table scene, where Welles uses a montage to convey the passage of time and chronicles the years-long collapse of a marriage in a few minutes.)
Welles and Toland’s compositions hide frames-within-frames (take the last time the audience sees Kane, walking through a mirror reflecting himself times infinity). “How Green Was My Valley” is more conservatively shot.
“Citizen Kane” is also simply more fun, thanks to the aforementioned quick pacing and playful humor abound. “How Green Was My Valley” has its moments of levity (when two miners give Hew’s abusive teacher a “boxing lesson”), but it’s mostly a solemn tearjerker, and so harder to watch. Since “Citizen Kane” goes down more easily so more people watch it, creating exponential growth in its standing as they sing its praises and convince others to check it out.