Only the knock-down-drag-out fight that ends the second act fails to register, in part because Rob Howell's distractingly spectacular deco-modern set isn't cluttered enough to let Elyot and Amanda whip up a sufficiently chaotic mess.
Gyllenhaal, often a distractingly tic-ridden actress who relies heavily on her sex-kitten sultriness, here shows unexpected backbone as a single mother coming to terms with her own bad habits as she takes yet another chance on a much-married man who's potentially crippled by his.