From the box office discussion on the movie search:

bad1996: "At 78.2% collapsed in the second weekend of the Russian «Stalingrad»."No one doubted the failure. Why go to Stalingrad when there are 300 Spartans?

Boris9999: Why go to Stalingrad?

Cheshire dog: It’s a pity that the Germans didn’t think about it at the beginning of the 40s.