Adolf Hitler’s rise to power is a fluke. He was made chancellor for political expedience by people who thought they could use him. Had there been another election, the National Socialist party would likely have lost many seats in the Reichstag. It would have been rendered weak.
One of the results of experience in Poland was the development of impromptu tank destroyers. When the Panzer I proved itself obsolete as a combat vehicle, some were relegated to patrol and garrison duties. The rest were converted into command tanks - a mobile radio station - ammo carriers and self-propelled guns. For the latter, the turret was removed and the fighting compartment cut open. A Czech 47mm gun was placed on top in a lightly-armored superstructure. This was the start of the German army as recycler. Rather than scrap obsolete vehicles, the Germans transformed them into tank destroyers. They were literally mobile antitank guns. Some were also converted to self-propelled artillery. The Marder series used Panzer II and Czech 38T tanks chassis to mount 75mm anti-tank guns. Panzer IIs were also used for self-propelled 105mm howitzers and were known as the Wespe. When the Panzer III was becoming obsolete, many were converted to Sturmgeschutz assault guns with the long 75mm gun or 150mm howitzer.
After the Normandy landings, Allied troops remarked that the Germans were so desperate they were using horse-drawn transportation. In fact, the Germans had been using it all along. Realizing their dependence on foreign oil and seeking to minimize the problem, Germany opted to fill the gap with horse-drawn equipment. They felt that as infantry divisions moved at the pace of men, the use of horses would be reasonable. So it was the many infantry divisions were using mostly horse-drawn transports and artillery. Of course, Germany had a massive veterinary corps as a result. Japan had come to the same conclusion and used horse-drawn equipment by infantry divisions in China.
German ammunition was less than reliable. After 1942, dud artillery rounds were common. American officers commented on the large number of dud round fired by German artillery in Normandy. Again, shortages of critical materials and sabotage by forced labor was a large problem by 1944. Another example was the panzerfaust antitank launcher. Many were sabotaged by laborers throwing a handful of sand into the warhead. That is a very dire moment for a soldier when his weapon fails to explode while facing down an enemy tank!
The German grand strategy was of Prussian origin. Frederick the Great came up with a way of war that involved quick maneuver, officers trained to take the initiative and quick victory. He knew that a smaller country like Prussia could not win a long, drawn-out war of attrition with larger enemies. Victory had to be gained before the war of attrition began. Thus, the idea was for victory to be gained in two years or less. The best example of this thinking was the Franco-Prussian War, where a German army of maneuver defeated the French. German forces on the Eastern front were able to implement this kind of warfare during World War I, but they were stalemated in the West. Germany was much a victim of attrition in 1918 as it was enemy strategy. The World War II army should have achieved victory by 1942, according to the plan. Once again, Germany ended up in the war of attrition that it had wanted to avoid.
The German army proved more dangerous in the retreat than in the attack. More casualties were caused by Germans in retreat than those on the offensive. They would fight to the last minute before retreating again and setting up another defensive position. In Tunisia, retreating German were known to fake surrendering, and then throw a grenade or use a machine gun on the troops coming to capture them. That backfired. Once word got around about fake surrenders, any German trying to surrender was likely to be gunned down on the spot.
Why did Germany keep fighting even when it was obvious the war was lost? The leadership, especially Hitler, hoped for a miracle weapon that would end the war in their favor. The miracle never came. This "super weapon" mentality affected German weapons. Rather than concentrate on enough numbers of good tanks like the Panzer IV H, much effort was spent developing new weapons that were more complex and harder to manufacture. They were also a greater strain on resources. The Panther and Tiger tanks were great weapons but came in too few numbers. Germany never really grasped the idea of war as being a game of technology AND numbers. They could have a thousand Panzer IVs for half as many Tigers and Panthers. The super weapon mentality slowed production and decreased numbers of available vehicles.
Russia understood war as a numbers game, but did not quite grasp the need for technology and quality. Ironically, as its training and equipment improved, so the numbers and quality of German equipment began to deteriorate. Nonetheless, even in victory the Russians lost three to five times the casualties that the Germans suffered.
As an aside, Germany placed emphasis on manpower and technology. Japan, its Asian ally, focused on the man rather than the equipment. This did not prove well for the Japanese, who lost many men to superior American firepower.