Not to sound tape-loopy, but “the reasons for the voltage are Kristen Stewart‘s scrappy performance as Joan Jett, the Runaways co-founder who went on to become a solo rock legend in the ’80s, and Michael Shannon‘s as L.A. rock impresario Kim Fowley. As long as the film is focused on [these two] and the generally pungent ’70s atmosphere, it radiates badass attitude and seems authentically plugged in to the spirit of ’70s rebel rock.”