It is cliched and pointless to say that Hitler was a monster. He was a human being, as we all are, but the circumstances around his life and times allowed for his hatreds to find sympathisers and an horrific outlet.
There have been many film portrayals of Hitler over the years but most of them are shockingly bad. The Robert Carlyle one being particularly awful.
There is a tendency to caricature vile figures from history because to act a truthful portrayal means that you have to emphasise with the subject. Ganz does this astonishingly well. You have to get your hands dirty to show multi-facets of Hitler, even a tender side to his personality - shown to those that he believes deserve it.
This was one of the very, very best screen performances of all time, in my opinion. Incredible
PS - I would take issue with the comment of Spencer Kissack (the originator of this thread) that states that Hitler brainwashed a country to fulfil his ends. This cannot be true and lets a huge number of Germans of that time off the hook.
Hitlers message became popular because of the psychological damage that the First World War inflicted on the German people and he also exploited the racial hatreds prevalent at the time towards Slavic peoples, Jews and others to gain power