It's easy to get engrossed in Black Mass because every scene is simply bursting with the promise of more. Unfortunately, it's a promise that never gets fulfilled. I don't know much about the real people this movie deals with, or the book it's based on, so I can't speak to it's accuracy or faithfulness, but as a movie- an entertainment vehicle and nothing else, it's merely adequate. Which is kind of painful to say because Johnny Depp's performance as crime lord James 'Whitey' Bulger is absolutely fantastic. It's just also unfortunate that the movie is neither actually about him, nor does it ever give him much to do. The movie is actually about the FBI agent who seeks to make an alliance with Bulger. Yet, he's much less the interesting character.