It's decent, and maybe it's notable for doing multiple things AT THE SAME TIME, even if most of them weren't actually done for the first time. (it's a risky game anyway, as people always discover another film that did something earlier anyway). Still, I prefer Ford's film shot by Toland, and Welles made better movies, too. I've seen Citizen Kane twice (same as Alien) and I just don't love it.
My recollection is that the first time I saw it was in a movie history class in college. The prof stopped the movie about a hundred times to explain why it was important that Kane glanced left rather than right or why that chair in the office was tilted, or whatever. That spoiled it for me....over-analysis. Since that fateful day, I have watched without interruption a couple of times, but it's still "pretty good" to me; a cinematic bag of tricks. I can think of lots of movies I'd rather watch.