Glad to be the first one to land on this thread (see what I did there?)
As a detached Englishman I was able to enjoy the spoof antics of Iron Sky to the full, with no squeamishness. It was fully tongue-in-cheek, as you know, and I even felt myself wishing sometimes they'd given the theme (preposterous as it was) a bit more of a serious sci-fi treatment, rather than so much of the "Carry On" style slapstick as there was.
Fantastic effects and I understand much of the film (including design of sets and spoof Nazi Lunar hardware) was the result of fan effort and finance.
Great news that there's another one planned.