How effective was Nazi propaganda? Did it actually bring around people ordinarily opposed to fascism like public critics of the regime or similarly disposed intellectuals? Were there elements mocked by the general public?

IMO- the purpose of propaganda was not to convince people to change their opinion on fascism, but to really enflame the already large and loyal populace. If you look at some of the propaganda of the time, for example "The Eternal Jew", there is no attempt to convince the viewer to change their views, but more to encourage the hatred of Jews.