Recorded behind a veil of secrecy that would make David Bowie raise an eyebrow, Sweden’s seminal artrockers Cult Of Luna have announced that a sequel to January’s staggering, Metropolis movie-inspired Vertikal opus, cunningly titled Vertikal II, is due out on September 20 via Indie Recordings. Even more expansive than the full-length, and featuring a remix of the track Vicarious Redemption by Godflesh founder Justin K Broadrick, Vertikal II is mindbending…