Downfall was an obscure but relevant movie (story) that sheds light on Hitler's mental state and the fragile condition of the Third Reich in its final days. Based on historical accounts I've come across in years studying the period as a hobby, including accounts from witnesses residing in and present at crucial points in the Bunker, recorded interviews with Axis and USSR military personnel, many of course represented in the movie, the accounts and events were for the most part accurate.
It's a powerful story although it tended to project a human angle towards Hitler. The guy blew his brains out after a murderous reign.