Live ammunition was used in the film - in interviews, actor Aleksey Kravchenko has described actual bullets passing some 10 centimeters above his head.
Some of the German soldiers are using Russian weapons - this is correct, as they were less likely to jam and could work at lower temperatures than many German-made guns.
Many of the uniforms seen throughout the film are originals.
The Nazi German SS Major Sturmbannfuhrer's type of pet in the film is an animal known as a Red Slender Loris, a mammal species of prosimian, i.e., a primate that is neither a monkey nor an ape.
The director planned to have Aleksey Kravchenko hypnotized by a psychotherapist during the most dreadful and violent scenes so that they wouldn't affect his young mind. However, turned out not to be susceptible to hypnosis and had to pretend all the way.