but why does everything I've ever heard about it focuses on the lyricism and ignores the dark humor pervading it? I don't see how you can hear Spacek's narration and not read into it some irony (on the behalf of the film, not of Spacek's character).
Also, it would make an interesting companion piece to the Coen Brothers' True Grit. Both feature female leads and narrators who are introduced into a world of violence starting with the murder of their father, then find themselves being dragged along by older men. And at the end, their efforts feel empty and leave them marked. The visual tone of the films is also similar, elegiac and beautiful while showing some really messed-up stuff happening.