On the positive side, the acting performances by the teenagers incarnating the two brothers are stellar. The changes of locations keep the movie entertaining and give it an epic touch. The addition of numerous quirky side characters who are trying to find ways to hide their fears adds diversity to the film. There are a few memorable scenes such as the father beating up his own son to teach him how to deny his identity, the younger brother stepping up to save a family of collaborators in an act of civic courage and the same character desperately running after his desperate sweetheart whose family just got attacked by an angry mob.
On the other side, the story doesn't offer anything new, is slightly dull and slow-paced in the middle section and only touches the surface of several interesting characters such as the Jewish doctor or the family of collaborators. Several chapters from the novel aren't included in the cinematic adaptation and a few details are also changed. Instead of showing the brothers endlessly wandering across mountains, the film should have spent more time developing the numerous interesting side characters and giving some additional information about the historic background.
In the end, A Bag of Marbles is ultimately a good film but suffers from being just another movie about the fate of a Jewish family during the Second World War. The movie itself has its reasons to be, has a quirky and epic approach going for it and convinces with two really good lead actors. However, European cinema has been saturated with movies of this kind over the past three decades and this film fails both to offer anything new and to compete with its numerous competitors. The most authentic, gripping and sinister movie of this kind is the outstanding The Pianist. But if you really want to get an idea of the horrors of the Second World War, you have to visit a former concentration camp which is an absolutely life-changing experience.