I actually caught the movie at the theater when it first ran a few years ago. While it was not a perfect movie, it was for the most part historically accurate, even going to the extent of showing Luther overtaken with his rages, in which he would rant and rave like a madman. As the movie ends after the signing of the Augsburg Confession, Luther isn't shown in his later years, after the catastrophic illnesses he managed to survive had taken a toll on his mind, during which time he wrote his ugly Antisemitic tracts. Still, as a Lutheran myself, I very much enjoyed seeing the old man portrayed on the big screen.
-Bill, otherwise known as Kraichgauer