INSIDE LLEWYN DAVIS Man. That cat does NOT appreciate folk music.

LET'S START with the cat. The orange tabby in Inside Llewyn Davis might be the greatest onscreen feline since the Coury-brand-demanding cat at the beginning of The Long Goodbye. We end up seeing much more of the kitty in Inside Llewyn Davis, Joel and Ethan Coen's caustic, marvelous depiction of the Greenwich Village folk-music scene of the early '60s. Down-on-his-luck folksinger Llewyn Davis (Oscar Isaac) totes the furball around with him for much of the movie, after he accidentally lets it out of a friend's apartment and locks the door behind them both.

You probably know someone like Llewyn—a bearded musician who surfs from couch to couch without a penny to his name, bumming cigarettes and meals wherever he can. He doesn't even own a winter coat. Llewyn's not a bad guy, necessarily, but there's just something about him that pisses people off. "Everything you touch turns to shit—like King Midas' idiot brother," a fellow folksinger (Carey Mulligan) tells him after revealing he may be the one who got her pregnant.

Llewyn's the latest in the string of feckless antiheroes that populate the Coen brothers' best movies, and Isaac turns in an exceptional performance that not only fulfills the role's technical challenges—that's Isaac singing every note and plucking every guitar string you hear—but allows you to find some affection for this prickly, troubled character. Indeed, Inside Llewyn Davis excels at every challenge the Coen brothers put up to it, succeeding not just as a richly appointed period piece or a movie musical, but also as the sort of riddle-like cinematic puzzle the Coens concoct so well. (The film's Möbius-like structure and symbolic undercurrents will have Coen fans obsessing for endless rewatches.) It's also the Coens' funniest since The Big Lebowski; a show-stopping scene of Isaac, Justin Timberlake, and Girls' Adam Driver recording the novelty song "Please Mr. Kennedy" is riotous.

And that cat!