How can this movie possibly work?

Rating: 9/10 (14 April 2019)

... but it does! Like Life is Beautiful, or for that matter Hogan's Heroes, this movie uses its dark backdrop (the Soviet Union during Stalin's purges) to build a comedic masterwork. Central to the humour is the fact that Stalin's repression left everyone terrified, even the members of the Politburo, who are adept at instantly reversing their position on any subject, at any time.
Simon Russell Beale does a wonderful job as the utterly amoral Berya, but I think three actors stand out even more: Jeffrey Tambor as the magnificently indecisive Malinkov, Steve Buscemi as a scheming but oddly principled Krushchev, and in particular Jason Isaacs as the straight talking, take-no-prisoners Field Marshal Zhukov.
In addition to being tremendously funny, it is also an excellent history lesson and a peek at what repression was like under the Soviets.