It's a feast for old-school Sabbath fans.
There's are explicit nods to some many past songs, (virtually?) all original line-up ones from single licks and guitar sounds up to Zeitgeist being an explicit companion piece to Planet Caravan.
Not to mention starting with a pretty definite mission statement: 'Is this the end of the beginning? Or the beginning of the end?' and closing with an exact mirror of the opening of Black Sabbath.
An absolute masterpiece of an album that sucked me in on first listening because of its combination of utter familiarity with completely new arrangements.
Brad Wilkes captured poor old Bill Ward's feel as well - details like keeping the beat on the bell of a crash cymbal.