Everybody has the old sniper duel story, but I have never been able to find a documented historical event. They have a Carlos Hathcock version from Vietnam, he was one of the all time greats in competitive shooting and sniping, he had the skills to pull it off. But again the documentation is crap and the "recovered rifle" which would be a great prize for the Marines "disappeared" after he got back to base.
As for the battle of Stalingrad, it was as terrible as mentioned with the stupid love story. On german story I read ,noted with disgust that with Nazi political officers forced them to send political bullshit material, political films and rubbers and std booklets in place of ammo, food, clothes and medicine. They figured it would be a short term thing, until Hitler ordered them not to be relieved and send a message to fight their way out. He reasoned if they had gas and ammo to make it to German lines , they had enough to attack and go forward.
The USSR had executed nearly every decent officer in their armies at the order of Stalin in the pervious years and tortured nearly every skilled soldier and soldier with experience to death or sent them to gulags. Lucky for them ,they have terrible weather.