Blitz, an authentic and astonishing recreation of London during its blitzkrieg by the Germans during World War II, pushes the artistry of Steve McQueen (12 Years a Slave, NYFF51) to ever more impressive levels. Working on a vast scale, McQueen sets things at human eye level, telling his original tale from the parallel perspectives of working-class single mother Rita (Saoirse Ronan) and her 9-year-old son, George (newcomer Elliott Heffernan), as they become separated within the labyrinth of a city under siege.