First time Robert De Niro plays a dual role.
This is the fifth collaboration between Barry Levinson and Robert De Niro after Sleepers, Wag the Dog, What Just Happened and The Wizard of Lies.
According to the plot listed above it says Frank Costello and Vito Genovese ran two different crime families. That's false. They were both a part of the same crime family, the Luciano Crime Family. Named after infamous mobster Charles "Lucky" Luciano. It later became the Genovese Crime family which is what it's currently known as.