Somewhere around the Oprichniki's song-and-dance number, I lost track of the Boyars and started wondering whether Joseph Stalin had commissioned his own nightmare.
The Boyars' plot, it turns out, is simple. Yefrosinia wants Ivan dead and her hapless son Vladimir crowned, so Ivan dresses the lad up as Tsar and lets her own assassin do the rest. Horribly clever.
Sergei Eisenstein carves everyone out of shadow until their faces look like cathedral masonry. Serafima Birman's Yefrosinia is the pick: grotesque until she finds her son's body, when the grief hits with a thud. Nikolai Cherkasov looms into every room like a coat stand with a grudge.
Then comes the colour banquet: red and gold, drunken Oprichniki, and Ivan watching like a spider. Unforgettable and baffling.
The trouble is Eisenstein sometimes buries the plot beneath all that symbolism and ceremony. Stalin's objections were largely political, though irritatingly, the charge of "formalism" has a point.
Part One made power look magnificent and faintly terrifying. The sequel drops the "faintly".