Even though the title says Donnie Brasco this movie is really about Lefty Ruggiero. Lefty, Al Pacino, is a small time gangster who's never able to climb in the ranks of the mob despite his time and efforts. Lefty is the one who brings Donnie Brasco, Johnny Depp, into the mob not knowing he is an undercover FBI agent. After some time Brasco starts to like Lefty and feels guilty about setting him up. There are some slow periods in the film but for the most part it is entertaining. There is some violence but it isn't gratuitous. Pacino turns in another remarkable performance as a mobster. Depp does a very good job too.
