Festival hit Anvil! The Story of Anvil, Sacha Gervasi’s documentary about the little-known titular metal outfit that was poised for stardom in 1984 but wound up falling into obscurity, finally gets the theatrical release it deserves this Friday. A touching portrait of friendship as well as a kick-ass ode to perseverance and the enduring appeal of squealing guitars and roaring vocals, Gervasi’s doc epitomizes much of what’s great (the ferocity, the personalities, the never-say-die ethos, the outrageousness) about heavy metal. To truly appreciate how right Gervasi gets his subject matter, however, one would be wise to first check out The Decline of Western Civilization Part II: The Metal Years, Penelope Spheeris’ 1988 follow-up to her 1981 doc about punk rock, and a cultural artifact that typifies just about everything embarrassing and awful about the genre. Opting to focus on interviews at the expense of prolonged concert footage, Spheeris winds up wasting considerable time on shallow, sex-crazed, idiotic nobody musicians and metal fans in and around the L.A. metal scene. Despite being fond of some of the bigger featured artists (Ozzy Osbourne, Aerosmith, Megadeth, KISS), Spheeris nonetheless allows many others to make fools of themselves, their decadence depicted as destined to lead them to the same dead end already occupied by W.A.S.P.’s Chris Holmes, who’s infamously seen sloshed and pouring vodka on himself in a swimming pool while his mom watches. With a few notable exceptions, that’s all what Decline amounts to – a snapshot of brainless flashes in the pan who, unlike Anvil’s bleeding, sweating and tearing Steve “Lips” Kudlow and Robb Reiner, prize self-destructive materialistic excess over the music.