This siege utilized massive, 400-foot long artillery guns to level Soviet structures and fortifications. Although this could have been done more efficiently with low-level German dive bombers, such as the Stuka, this method was effective enough. The Germans defeated the Soviets, although this method was not as effective as the blitzkrieg had been farther north.
Gas was used against defenders holed up in caves. It was one of rare uses of gas during WW2.