When you’re talking all-time greatest slabs of hard rock party music, Van Halen’s debut is right up there with the best of them. Young Diamond Dave is a samurai on the mic—twirling, somersaulting, and slicing through the humongous sound with brilliant theater. Eddie Van Halen is innovation incarnate; on rippers “Runnin’ With the Devil,” “Jamie’s Cryin’,” and “Ice Cream Man,” the guitarist’s coldly precise harmonics transform post-Hendrix licks and riffs into the ecstatic shrieks of alien robots. “Eruption,” his mind-bending solo piece, represents an entirely new language in feedback, distortion, and technique.