Black :
# Lyrics, often taking the form of Satanic themes which blaspheme Christianity, and other occult themes, like paganism (this is the hallmark of Black Metal, but is not exclusive to it. Bands such as Slayer, Deicide, and Immolation overlap lyrically with black metal somewhat, but are generally not referred to as black metal)
# heavy distortion
# fast, aggressive drums, often including blast beats
# fast, repetitive guitar playing (so-called tremolo picking, in which the guitar is played similarly to balalaika) and riffing
# high-pitched screeching vocals
# swift percussion
# repetition
# cold and sad atmosphere.
etc etc....