Looked at Visconte' Ossessione (1943) and it's gorgeous, maybe my favorite Visconte until The Leopard. Lovely little touches here, and there--like when Calamai sits down and first pours her heart out to Girotti, Visconte inserts a shot of him listening to something (a seashell, I think), and in his innocence, hands it to her to listen (she does with a touch of maternal indulgence). It's a lovely touch, the implication that Girotti's a boy in a man's body, an innocent to possibly be duped, or fallen in love with. You can't help but fear for this big boy.
And the neorealist trappings work so well with noir--the grit, the sweat (you can smell the exhalations off the fat husband's armpits), the harsh sunlight on paving-stone streets capture the spirit of small-town noir so much more beautifully than, say the Hollywood version does (John Garfield is perfectly cast, but Lana Turner looks every bit the star she is to be a credibly slatternly housewife). And the two lovers here (Calamai and Girotti, who look anything but celebrities) feel more genuinely conflicted--their hearts wanting more than anything to trust each other while their brains tell them that's the last thing they should do (their brains are right by a mile).
If I remember correctly, the Cain novel has the lovers go scot-free, and then meet their fate; Visconte goes less for irony and more for that sense of implacable Fate, turning her wheels--which feels more in keeping with neorealism's sensibilities. Beautifully bleak.