The KV-2 was built as an artillery piece. They used the KV-1 chassis and gave it a short 152 mm gun to fight against bunkers. Due to the large gun, the turret had to be a lot larger than that of the original KV-1, so they had to armor it even thicker (because it was alot more visible and an easy target). The tank was slow and had a very slow rate of fire, which was a huge disadvantage. The turret could only be turned very slowly. It was unable to effeciently fight German tanks, despite the fact the Germans couldnt penetrate its armor, but it could be an effective road block until the Germans shot it with dive bombers. When the Germans conquered the KV-2 production sites, the Soviets stopped producing the tank, even in their alternative production facilities, because it turned out to be a complete design fail. So yea... having it in the game and not the KV-1 is a very strage decision... but maybe they change that. They really should.