It had to be the cold that done them in. Their training wasn't very good but Germans armored military was good. Too bad they didn't have the 21st to back them up. But in all the Germans should have been better equipped even if it meant lugging around a few extra pounds of gear to fight off the bitter cold. But non the less it's never smart to invade a country that is known for it's harsh conditions which the locals are quite used to.