The opening hour of Casino plays like a documentary, with narration by real-life mobster Sam “Ace” Rothstein (Robert De Niro) and others as they explain how they skimmed millions from Las Vegas casinos by stealthy methods. It is one of the most fascinating aspects of the film, which makes it more than a simple story about mafia crime. It is also a religious parable, an exploration of the way that mankind has been gifted a world that feels like paradise and then turned it into a nightmarish hell.

Scorsese’s characters are always preoccupied by the idea that their actions might be viewed. This is a recurring theme in his films, from the way that he has his characters wear their hair long to keep it away from their faces to the fact that low-level hoods like Ace keep detailed expense accounts that are used as evidence in court. It’s even present in the title of the movie, which refers to a type of gambling game called “blackjack.”

This is one of the most important elements of Casino because it suggests that the problem with vice and inequity is that it cannot remain hidden forever. Eventually, gangsters in Casino begin to believe that they are operating outside the law, and their sins are ultimately revealed by their own greed and shortsightedness. They end up getting spit out of the city that gave them their opportunity to thrive, just like the Teamsters who funded Ace’s gamble with his own money.