Thrash metal is an extreme subgenre of heavy metal music characterized by its overall aggression and often fast tempo. The songs usually use fast percussive beats and low-register guitar riffs, overlaid with shredding-style lead guitar work. The lyrical subject matter often deals with criticisms of The Establishment and concern over the destruction of the environment, and at times shares a disdain for Christian dogma resembling that of their black metal counterparts. The language is typically direct and denunciatory, an approach borrowed from hardcore punk.