Before and during the invasion of the Soviet Union in 1941 there was a struggle going on "behind the scenes" between the "old school" of prussian officers (most of them ww1 veterans) and the nazi regime. The above 10 rules are defenitely from the prussian side.
In the evening of june 21. the so-called "Commisar-order" was given: All soviet political officers, jews and partisans were to be handed over to the SS or the "secret field police". (Feldgendarmerie...? I'm translating this out of a norwegian copy of Anthony Beevor's "Stalingrad"...) All intelligence and most staff officers were given Field Marshal von Brauchitsch's order drawing up the "special tasks" of army commanders, SS Sonderkommandos and the Sicherheitsdienst (?) operating behind the front in "this final struggle between two opposite political systems". Finally, a "juridistiction (did I get it right...?) order" denied russian civilians every right to appeal, and also practically aquitted soldiers of committing crimes against civilians in advance, including rape, murder and looting. This order was signed by Field Marshal Keitel.
Many officers of the prussian school were horrified by these orders, and many refused to pass them on to their men. These, however, were the minority. Hitler had made it very clear in his speeches, that the war to come would be a "war of annihilation" against the "bolshevik commisars and the communist intelligensia".
In my opinion, the german army "lost most of its innocense" in 1941, finally caving in to the nazi world view. Wermacht became directly involved in massacres of jews and communists officials. Even General Erich von Manstein, who on private occations would admit he was partly jewish, proclamed after assuming command of I army: "The jewish-bolshevik system must be torn up by its root once and for all".
I guess that'll be enough for today.