His works encompass novels, essays, drama, poetry,... It is Krleza, from the former Yugoslavia, who should obtain Nobel prize for literature, not Ivo Andric (a Bosnian Croat shfting voluntarily into being a Serbian writer, hardly there could be a more politycally correct writer for former YU)- but this would be too much for Serbs, so Krleza never made even to being an official candidate from the Yugoslavian side. Something similar to a case of Zbigniew Herbert in Poland (where he definitely would be a logical pick instead of Wislawa Szymborska, after Milosz was already awarded it). Award itself here is not important, but it brings wider knowledge of a writer, and it is indeed a cultural crime to rob the wider world audience of writers like Herbert or Krleza.
In his large opus, Krleza is today most often present in theatre and TV with a cycle of three drama works on a North-Croatian family of Glembay, notorious petty-bourgeois post-feudal capitalists. It is a violent drama cycle, with corpses of lovers and ruined existences falling at the floor in the finals. As Krleza was pre-cursor of existentialism (writing such works well in advance, 10 years before Sartre), his heroes mainly theatrically kill themselves, after a vicious and ruthless self-questioning, tortured by the equally vicious and ruthless reality of their doings and shortcomings.
A drama cycle "The Glembays", "In agony" and "Leda" are three works where Krleza gave a tomography of rotten patrician bourgeouis world of Zagreb at the beginning of the XX ct. Nothing is real here, everything is rotten and false, guided by lowest instincts and money. Honesty is virtually non-existant, even-or especially in-emotional relationships.
Mixed with Krlezian existentialist observations of the world, this work lucidly shows an agony of the falling society. While local in its scope, it is of a general austro-hungarian spirit, and could be well understood all through the lands of the old Empire even today. In this sense it is definitely defining a wider Central-European experience.