Grunge is generally characterized by a sludgy guitar sound that uses a high level of distortion, fuzz and feedback effects. Grunge fuses elements of hardcore punk and heavy metal, although some bands performed with more emphasis on one or the other. The music shares with punk raw sound and similar lyrical concerns. However, it also involves much slower tempos, dissonant harmonies, and more complex instrumentation – which is reminiscent of heavy metal. Some individuals associated with the development of grunge, including Sub Pop producer Jack Endino and the Melvins, explained grunge's incorporation of heavy rock influences such as Kiss as "musical provocation". Grunge artists considered these bands "cheesy" but nonetheless enjoyed them; Buzz Osborne of the Melvins described it as an attempt to see what ridiculous things bands could do and get away with. In the early 1990s, Nirvana's signature "stop-start" song format became a genre convention.
Lyrics are typically angst-filled, often addressing themes such as social alienation, apathy, confinement, and a desire for freedom. A number of factors influenced the focus on such subject matter. Many grunge musicians displayed a general disenchantment with the state of society, as well as a discomfort with social prejudices. Such themes bear similarities to those addressed by punk rock musicians and the perceptions of Generation X. Music critic Simon Reynolds said in 1992 that "there's a feeling of burnout in the culture at large. Kids are depressed about the future.” Humor in grunge often satirized glam metal—for example, Soundgarden’s "Big Dumb Sex"—and other forms of popular rock music during the 1980s.