The boss player's encounter known as "The Jesus" shares the same name and personality as the John Turturro character from "The Big Lebowski". Much of the NPC dialogue is lifted from film characters. Many generics NPCs will say "Forget about it huh", which is another line from "The Big Lebowski" and many female NPCs will quote Jules Winfield from "Pulp Fiction" with such lines as the "That's cool and the gang!" phrase. Gameplay in "Kingpin" was most noted for its profanity laden dialog and its graphic depiction of violence. An idea incorporated into the game was that of area-specific damage: a shot to the head deals more damage than a shot on the leg. To complement this, each game character also has a deformable skin, which indicates where and how badly the character had been injured. Injured characters also bleed, and leave a blood trail making it easier to follow them. Instead of having a universal armor value for the player, armor is split into three different types, helmet, body armor and leggings, with separate values for each one. Another innovative feature of the game is the use of weapon modifications. Various mods can be used to upgrade the weapons in the game. The pistol, for example, can be modified to increase its firepower, or its rate of fire, among other things. "Kingpin" also features heavy NPC interaction for a first-person shooter; the player can interact with NPCs and choose between positive or negative responses. This can lead to various outcomes such as gleaning new information, hiring gang members, or provoking an enemy into attacking. The NPC response to the player also takes into account whether the player's gun is holstered or not. Some areas, such as bars and clubs, which acted as hubs for the chapters, force the player to lower his weapon. The player can also hire gang members to join him, and in some cases this is necessary as the player would need an AI character's specific skill. Another new feature is the introduction of cash. Fallen enemies can be searched for cash, which can then be used to purchase weapons and ammunition at the Pawn-O-Matic, a shop found in every chapter, except in chapter five. Cash can also be used to hire gang members. The soundtrack for "Kingpin" was provided by the rap group Cypress Hill, and featured three tracks from their album IV. These were: "16 Men Till There's No Men Left", "Checkmate", and "Lightning Strikes".