Gil has posted a query on BoardGameGeek that will get you thinking outside the box. Pushing your Panzers forward can be blocked by better Soviet planning. The Soviets must have a balance between standing and fighting to slow the Axis down and running. If you retreat to quickly, the German HQs can setup and support attacks on Moscow other key cities. If you do not retreat fast enough, your army can see pockets trap units or just loses from strong attacks.