Motherhood becomes a psychological battleground in writer-director Mary Bronstein’s gripping second feature, which casts Rose Byrne as a working parent unable to slow her downward spiral. If I Had Legs I’d Kick You puts us in the frenzied head of its main character, who loses her equilibrium after a series of accidents, stresses and poor decisions puts her at a breaking point. The film starts off at maximum intensity and only increases from there, examining parental guilt and our self-help culture as Byrne’s character implodes. New York therapist Linda (Byrne) is raising her young, very sick daughter (Delaney Quinn) practically on her own. (Her husband Charlie, played by Christian Slater, is just a voice on the phone, always away for work.) Early on, her apartment ceiling caves in after a massive water leak, forcing them to stay in a seedy motel while she waits fruitlessly for her superintendent to fix the damage. But this is only one challenge for Linda: she also must contend with a needy, possibly unstable client, Caroline (Danielle Macdonald); her own increasingly frustrated therapist (Conan O’Brien); and a concerned physician, Dr. Spring (Mary Bronstein)-Screen Daily