While its easy to assume that most of what became celebrated in Soviet media was exaggerated or even fiction - Zaitsev and many others were caught in a cycle of glorification and reportage that wanted to show the cost to the Germans for invading The Soviet Union. Zaitsev's story seems fantastic and even exaggerated, but he wasn't alone in having high kill counts during the course of Battle of Stalingrad. Snipers were deployed en masse during the battle to terrorize German soldiers and to slow their advance on the ruin city - making each corner and street a fatal test of nerves. soldiers such as Vasilij Kvachantiradze had comparable amounts of kills in different operations - in Kvachantriadze's case, Bagration.

On the other side, snipers such as Simo Hayha had an even greater amount of confirmed kills than Zaytsev did, in a smaller amount of time - in worse conditions, without the assistance of a telescopic sight. So there may have been some work of exaggeration in Soviet reporting be it in Pravda or the various newspapers for Red Army soldiers, but it isn't wholly unlikely that Zaytsev really was the marksman he was reputed to be - developing tactics such as the 'Three Sixes' - putting three teams of snipers and scouts paired together in separate locations to cover a wider area, a doctrine adopted by modern Russian forces.

In general Soviet forces took great pride in their abilities at camouflage known as Maskirovka - snipers, forward observers, and artillery spotters went to great length to conceal themselves more and more effectively as the war progressed. Artillery spotters considered themselves almost like snipers in their own right - hiding themselves from concealed positions to rain down fire on the enemy.

In short - there may have been some degree of exaggeration, but the conditions of the battles he fought in were conducive for him and his fellow snipers to rack up large amounts of kills using innovative tactics that inspired later generations of marksmen. Soviet snipers strove to better their kill count and actively engaged in competition with their comrades in order to eliminate as many Germans as they could

sources: Antony Beevor's Stalingrad, Fall of Berlin, Cummins Cataclysm, Busch survivors of Stalingrad