What are the various mafia cards roles and how do they impact gameplay in the Mafia card game?

In the Mafia card game, there are various roles such as the Mafia, Detective, Doctor, and Civilian. The Mafia's goal is to eliminate all other players, while the Detective tries to identify the Mafia. The Doctor can protect players from being eliminated. These roles impact gameplay by creating deception, strategy, and deduction as players try to figure out who is who and make alliances to survive.