During World War II, he led the Croatian production, directed, wrote, produced and edited the film, and after the war he continued with the director and editor work even on a feature film.
Marjanovic directed the film Ciguli Miguli, a 1952 Yugoslav political satire.
It was meant to be the first satirical film of the post-World War II Yugoslav cinema, but its sharp criticism of bureaucracy was politically condemned by the authorities and the film was banned as "anti-socialist".
Giving up film making, he devoted himself to documentaries about nature ("Small Miracles of nature big", "Marmot," Griffon Vulture ").
He received the Vladimir Nazor Croatian State Award.