First off, the majority of trained snipers were up north in lenningrad, trying to save the poor 4 million people who were trapped there.
And artillery was used well in the battle of stalingrad, how else do you think he outflanked them. And few pure human attacks were used, it was much more concentrated on blocking all help and support from germany for reaching stalingrad. Zuchow (That's how the russians say his name), places his troops just right to keep them encircled. Yes russians died, but that's war, just as many germans died too. Stalingrad was a huge success for Russia.