Well as you can imagine a biopic of Al Capone and the Chicago gangster scene in the 1920s is not for the faint hearted, indeed this film can best be described as violence and more violence. Capone is played by Ben Gazzara and we don't see much at all of his early life but rather how he gets involved with Johnny Torrio (Harry Guardino) then a trusted lieutenant of the Italian mafia boss in Chicago.
Capone helped Johnny take over the mob and then assists Johnny in making it big during the Prohibition years. Eventually amid open warfare with rival gangs Al Capone has Johnny (nearly) killed and takes over the mob himself. The story of the film is never trust your lieutenant as he will take over from you in the end, as happens to Capone himself when he is betrayed by Frank Nitti (Sylvester Stallone) and he ends up in Alcatraz...
Well the film is pretty low-budget and it shows at times but it is undeniably thrilling. If only we could see a bit more about Capone's early life and his motivations. That might mean cutting out some of action scenes of course. It is a biopic though not very accurate, a true depiction of Capone's life would probably require a series of films to be honest but this can give you a taste.