This wasn't a Germany's war as much as it was Hitler's War. Hitler ran the show, entirely by the end of the war.
Hitler had gradually gained control of the Army, until by 1942, it was all but complete. There was no one to stop him by that time, von Brauchitsch (Commander in Chief of Army) being replaced by the Führer himself after the defeat at Moscow. Hitler had full, full control after this point, I cannot emphasize this more than enough. After February 1942, Hitler was the only person, the ONLY person, who saw 'everything' military in nature. He knew and was aware of most military matters, even if he ignored them. He made right and wrong decisions, but the fact of the matter is, he rarely took anyones advice, and no one truly knew how bad the overall situation truly was until it was too late. Even high-ranking generals like Manstein and Zeitzler knew only that their sectors of the front were doing poorly. They simply were either lied to, or not told. Along with the sense of German duty, they could only take limited actions to counter-balance Hitler's wishes, whatever they might be. They tried to fight back some times, resigning in single occasions, like Zeitzler (who was to become head of the Bundeswehr of West Germany in 1952), but did not have much success because their actions weren't collaborated enough. That was also the problem (along with bad luck) with those that wanted to get rid of Hitler, collaboration. Gestapo and SS were strong, but the overall sense of duty and military obedience dampened the resistance of the highest generals to disobey Hitler.
To blame Hitler entirely would not be fair either, he was assisted by many many willing opportunists, thieves, murderers, lackeys and such. His reign was criminal, but the German people as a whole didn't know what was going on.