Many reviews seem to miss the complicated layers of Czech culture, and hence view The Cremator only through western lens.
The politics and historical background of this film play heavily into the story. The director Juraj Herz had been a prisoner in a concentration camp and thankfully survived the Holocaust and went on to make movies. So the film was about the Nazi occupation made by a Jewish director who survived the Holocaust and later filmed during Czechoslovakia's oppressive communist regime (following the Prague Spring). Quite a complicated layer for Americans to swallow. The Czech people are a cynical bunch and understandably trust no type of government. Their culture and worldview (much like that of eastern Europe) remain a mystery to most Americans.
With that, he film was neither horrific nor depressing. It was a wicked comedy-Czech style, if you will. The cinematography was heavily stylized, almost Kafkaesque, and revealed a theatrical satire with odd moments of humor. The idea that this ordinary man with a mundane job could morph into a führer-like character illustrates perfectly the Czech skepticism toward humanity. The movie exposes the stupidity of people and politics, and its fatalistic outlook results in a clever tragicomedy.