My comments are directed to the claim that this film is based on a true story. The true facts of Henri Young's case are significantly different from the story told in the movie. For instance, Young was not just a petty thief when he came to Alcatraz -- he was already doing time for bank robbery and murder. Nor was he kept in an underground dungeon for three years as punishment for an escape attempt -- his punishment was served in an isolation cell on the prison's first floor with the normal facilities that all prisoners' cells had. His case did not lead directly to the closing of Alcatraz; it continued as a Federal prison for over twenty years after his trial. Of course, there were some abuses at Alcatraz (as at virtually all prisons). Young's trial had some impact on correcting those abuses, but not to the extent suggested by the film.
If you're interested in another view of the Henri Young case, visit the Bureau of Prisons web site (I can't give the URL because that would violate the comments posting guidelines) and search for "Murder in the First".
In any film based on a true event, some license must be granted to the screenwriter. There's no way they can know exactly what was said in every conversation, so representative dialogue has to be written. Some minor characters will probably be composites. These things are understandable. But when the film blatantly distorts the main characters and the main events of the story, I can't help but think that the point the film is making is probably built on shaky ground. "Murder in the First" may be entertaining in some people's opinion, but no one should come away from this film thinking they have seen history portrayed accurately.