I am used to seeing "leisurely" as an adjective exclusively, as in "walking at a leisurely pace." But today I read it used as an adverb in a New York Times review of "Abraham Lincoln: Vampire Killer." It seems archaic to me to use it so (emphasis added):
[The director's] first American studio effort, “Wanted” (2008), is a modestly diverting if finally tedious exercise in which the stylized violence almost upstages its star, Angelina Jolie. “Wanted” is the kind of contemporary studio fun that shows a bullet exiting a human head in slow motion, giving you time to marvel at how the skin around the wound stretches as the projectile leisurely rips through the skull.