What makes Swallowed in Black by Sadus notable?

'Swallowed in Black' received acclaim for its musicianship and is often cited as a key release in the evolution of thrash metal during the early '90s. The album contributed to Sadus's reputation, influencing numerous bands within the genre and helping to shape the sound of extreme metal. Released in January 1990, 'Swallowed in Black' marked Sadus's third full-length album, following their influential 'Illusions' from 1988. At this point, the band was solidifying its presence in the thrash metal scene, known for its technical prowess and heavy sound.