Other than the word itself "fascism" being a political movement. Imperial Germany (and earlier, Prussia) had undoubtedly had a strong, super-centralized (comparatively, at the beginning of its existence) model that emphasized military service and obedience to the state as being very high priorities, so what distinction is exactly made between the ruling style of the Kaiser and the Fuehrer? Other than the fact that one title is a hereditary and the other is an appointed one. In addition to the fact that Germany between World War 1 and Nazi rule had a brief interregnum of democracy; is the only distinction made between Fascism and "Prussianism" who's in charge/the way by which he gains that power?
A lot of ink has been spilled on how continuous Nazi Germany is with Prussia, or more specifically the Empire. Fritz Stern, Erick Eych and Christopher Clark have written accessible histories on the subject. I recommend Stern's "Failure of Illiberalism" especially.
First, it's a misconception that the state of Prussia was always tyranical, anti-liberal, feudal et cetera. In the 18th and 19th centuries it was amongst the more liberal states in Europe. Frederick the Great was a modernizer extremely tolerant, even encouraging, of immigration and religious plurality. He was no German nationalist and indeed thought the French language far superior to his native tongue. During and after the Napoleonic Wars, there was a reforming movement led by liberal bureaucrats like Baron Von Stein that abolished serfdom and sought to establish a more Republican order. The sort of feudal reaction that characterized the late Empire really springs from this moment, when military men and aristocrats began to defend their privileges against the reformers.
Bismarck and Kaiser Wilhelm II did much between them to encourage reaction, bur Germans still lived in a relatively tolerant society, and many welcomed democracy in 1918.
There were obviously, however, continuitiea between the authoriarian style of Wilhelm and that of Hitler, and the population was inclined towards authoritarianism. Still, Nazism was radically worse than anything that came before it in German history.