Everything is "German-perfect" in this film. However do not equal this comment to "coldness" or "steel-like perfect". Profound emotions are conveyed all along through it. I am a professional pianist/ composer/arranger/ orchestra Director myself, and yes, for musicians it is immediately evident the 12-yr old kid is ACTUALLY playing. Furthermore, he plays with emotion, virtuosity, sense of humor and wit!. The grandfather is played by great German actor Bruno Gantz (who indeed played one of the most realistic portrayals of Hitler I have seen, in "The Fall" - Last Days of Hitler -"..or something like that).
The original music is just wonderful, not to mention the rendering of works by the classical music masters!. The casting is perfect, and the story/script simply gets unbeatable due to the writer's avoiding the focus ONLY on the kid's musical virtuosity, but due to his high IQ he mixed in Internet (IT), wall street issues, business, parents-son relationships, grandfather-grandson relationships. I am the father of three (boy 30, boy 24 and girl 18) and also had a close relation with my grandfathers. Everyone is simply perfect. Don't miss it!.