His [Jirí Trnka’s] subsequent animation film, Pérak a SS, was more successful, especially because the story was based on tales that circulated in Prague during the German occupation about an elusive man of springs that tricked the invaders in a thousand different ways. This film, as opposed to the previous one [Darek, 1946], tells a story and is easier to understand. Pérak is an action film based on gags and chases. The comedy of the situations mingles with and is completed by the plastic humour. For example, when the SS troops run towards each other rather than bumping into each other they carry on running vertically upwards, rather mechanically. In keeping with the story Trnka chose a range of black and whites and often used a collage of photographs of city streets as a background, which increased the sense of authenticity.

Jean-Marc Boillat, Anthologie du cinéma, n. 8, 1974