fyeahmetal
IMO this is the alpha and omega of 2nd wave black metal, being a direct link from the 1st wave like Venom and Hellhammer to the classic 2nd wave template. It's perfect in its imperfection, from the random electronic intro by a German musician to the rawer-than-raw tones. Despite the caveman nature of the riffs, the first one is in 5/4, a surprisingly sophisticated opening salvo that helped set the stage for everything afterwards.
Favorite track: Deathcrush.