by Stephen Thomas Erlewine The mildly offensive album art -- essentially, it's a play on the album's title -- disguises the fact that NOFX's punk rock is hardly breaking new ground. Taking the heavy guitar attack of the Sex Pistols and melding it with the us-against-them mentality of mid-'80s American hardcore, NOFX winds up sounding like a conservative punk band with metal leanings. Some of the songs are standouts, but most of the album blends together. As an expression of adolescent rage, Heavy Petting Zoo serves its purpose -- it's basically just a barrage of heavy riffs and gut-busting bellowing -- but it doesn't hold up on repeated listens.