1.) Things like Enigma were miles ahead of the Allies. Much of allied nuclear, and processing technology was gleaned from the Nazis. This was so well known by Germans, that they often fed the allies fake information, especially about their nuclear program, to throw the allies off.
2.) While, I agree the V2 rocket was a LONG term project, that was not nearly close to being effective... it was groundbreaking. It cleared the way, and made possible the ideas of intercontinental ballistics missiles. The Nazis did not expect the USA to enter the war. Their weapons plans, were on a much larger timescale. Their "strategy" was to hold out in europe, create nukes, then drop them with stealth bombers on NYC, to make America(and the rest of the world) surrender. If the Nazis weren't being bombed all over Europe, they likely would have won WW2. The only reason the Allies beat them to the Nuke was because the Nazis had no airforce, no navy, and was focusing on falling back. It is also very likely that a "leak", or defector gave nuclear secrets to the allies. The Nazis, after the war, were found to have taken high altitute photos of NYC, in preparations of dropping the bomb on it, if necessary.
They never tested their missiles? Just built them? For the first time in history, somebody built a weapon, and didn't test it?
Northrop tested it, and foudn it had materials that absorbed waves. Then, they went back, and mysteriously, it's all gone. Nevermind, they completely made up the fact it was stealth, and NOW it's not stealth. Seems like some obvious coverup stuff to me. I mean, even with the second test, it still beat out British aircraft in terms of stealth.
We can argue about bombers. Stealth Subs were no argument. They had them. The Nazis, like I said, had long term weapons goals. They were not able to use their aircraft, or navy at all later in the war. Thus, they couldn't use any of their weapons, and many were never used in actual warfare. That doesn't mean the inventions were useless. The USA spent BILLIONS of dollars, and risked international warcrimes, and OVERTHROW by its people, for helping DOZENS, or HUNDREDS of nazi scientists escape the international courts, in return for revealing Nazi knowledge to the CIA/OSS.
Since then, both the USSR, and USA have tried to whitewash history, and claim the various inventions of the Nazis to be their own. Any idea that the Nazis created anything of importance had to be erased from history(both the Soviets, and USA, and all allies agreed on this). Northrop is a great example of this. They tested the Stealth Bomber. It came back with having a specific signature that proved it was stealth technology. Then, a while later, they go back, and rewrite history, by simply saying "never-mind, that substance wasn't there... we were lying... it's not really stealth technology... we invented it... like with all technology"