I think what worked about "Lonesome Jim" more than anything else was its simplicity, its ability to tell a story without the flashiness of special effects or cliched dialogue, and instead with acting performances from Casey Affleck and Liv Tyler that felt like they were not even acting. Superb direction from Steve Buscemi added to the realism, making it feel like pages out of a diary instead of a motion picture.
Interesting and oddball, Buscemi the director is about as unpredictable as his films - always character studies, sometimes to the point of excess but nevertheless interesting. Casey Affleck's awkward portrayal of a dysfunctional young man is touching and effective with a subtle performance by Liv Tyler.
Love Mark Boone Junior in this film. If you don't know him, you should.