Opera returns to Zurich’s 1,100-seat neo-Rococo candy box in almost all its grandeur. As Russia’s tortured tsar, Michael Volle has bark, bite, and physical menace galore to bring to the party. Barrie Kosky directs Mussorgsky’s gloomy epic in its longer, later form, including the “Polish” Act, spliced in for a burst of conventional razzmatazz that has no place in the opera’s original form—and which plenty of Boris purists would just as soon do without. Bowing to public-health regulations, the conductor Kirill Karabits, the orchestra, and the chorus will be piped in live from the company’s remote rehearsal location. —M.G.