The production unexpectedly ran out of money halfway through and halted for several months in order to find new investors. This ended up working in its favor, since Marcell Nagy was going through puberty, and by the time they restarted, he looked physically more mature, taller, and his voice deeper. By the time his character enters and survives the death camp, he looks several years older than when the film began, adding an element of reality that otherwise would have been created with make-up.
The Nobel Prize winning writer of the book "Fateless" viewed the true-to-fact set of the death camp Buchenwald, and he was shocked of the sight. He left the set in a short time.
With its estimated budget of HUF 2,500,000,000 (twelve million dollars), this is the most expensive Hungarian production to date.
When he was ill, György was taken to a tent with the word "revier" written on it. A revier in the language of concentration camps was a facility for sick inmates. The word is abbreviated from the German term, Krankenrevier ("sick bay", "dispensary"). The majority of the Revier's medical personnel were inmates themselves, and the conditions in reviers varied considerably depending on the type of the camp.