There is no doubt that also children were executed by Germans. In some cases whole villages were destroyed and all inhabitants killed as a reprisal after a partisan raid.
What I ranted against was the seemingly necessary innocent Russian boy that gets killed in almost every war movie that is placed on the East Front.
In Cross of Iron he is shot by Russians when returning from Germans.
In Stalingrad the main characters of the movie are forced to execute him by an eevil nazi major.
And now in Enemy at Gates an eevil german major hangs him to find the sniper.
As I mentioned before, the way the duel is presented in the movie is not even close to the account given by Chuikov in his book "Stalingrad" (that is the earliest one that I've managed to find, probably there are previous Russian sources).
There the story goes like this: Russian snipers have got notable successes and to combat them Germans send in the commander of sniper school. I don't think the commander is named in Stalingrad, but other sources identify him as "Major König". Then, several Russian snipers got killed by a German sniper on a specific sector of the front. Zaitsev then guessed that the expert sniper is active there, and started to hunt him. After several days they find out that he was hidden under a destroyed tractor (or tank, or something like that). The hiding spot was identified when a Russian comissar saw him, but the German shot the comissar before he had time to reveal the place to the others. However, the Russian snipers got the general direction and then few hours later saw sunlight reflecting quickly from the scope of the German. The next day they constructed an ambush where one sniper very carefully raised his helmet on a plank, and shouted "in agony" when the sniper shot at it. Then. the German raised his head for an instant, and Zaitsev killed him.
Nothing about hanging children, there.