Fahrenheit Gameplay
Console versions of the game eschew most of the traditional methods of control, making minimal use of the face buttons on the controller, instead using twin analog sticks for all player actions. The left stick controls movement of the character, and the right is used for context-sensitive actions. For instance, when Lucas approaches his table at the diner in the opening scene, one direction may cause him to take a seat, while another makes him examine his bill, and a third lets him pick up his drink and take a sip. The available options are displayed with simple diagrams at the top of the screen. Some more complex motions, such as climbing a fence or spinning a yo-yo in "around the world" fashion, require controller motions akin to those used for special moves from conventional fighting games.
During the tutorial of the game director David Cage instructs the player to move the thumb-stick slowly when opening a door, to maximize immersion, making it clear the prevalent use of thumb-sticks in the game was intended to increase immersion. The rare occasion in which the face buttons are used never directly control character actions, rather, the buttons (the Y, B, and A, or triangle, O and X, on Xbox and PS2, respectively) are used to interact with menus and user interface. This includes changing between characters, navigating menus in computer systems, and displaying the "mental health" of the character.
On the PC the game can be controlled by keyboard and mouse, with key movements and mouse gestures used in conjunction in lieu of analog control sticks, but Windows gamepads with analog sticks are also supported, and recommended.
There are also large action set pieces, which are completely scripted, but do require reflexes to complete. During these scenes, two circular diagrams with colored segments (resembling the electronic Simon game) are superimposed over the full-motion animation, each one corresponding to one of the analog sticks. The diagrams depict sequences of control inputs, which the player must mimic in order to maneuver the character out of danger. It is similar to the game-play of Dragon's Lair or the "Quick Time Event" sequences in Shenmue. The game also requires feats of endurance, involving the alternate pressing of the left and right shoulder buttons as rapidly as possible. These L-trigger/R-trigger sequences are generally used to evoke (and cause) physical strain, such as running or swimming.
The game provides each character with a "Mental Health" meter, which goes from full ("Neutral") to empty ("Wrecked") and represents the character's mental health. Many of the game's events (such as the opening, where Lucas comes over to the prone body of his victim) subtract points from the meter, but everyday or habitual activities (such as eating, urinating or receiving good news) will add to them, as well as scenarios in which the character makes a revealing discovery or action that helps him or her in some substantial way. An empty Sanity meter leads to an end depending on the character (Carla and Tyler will give up their badges, and Lucas will either turn himself in, or commit suicide) and a Game Over.
Finally, a conversation system is also implemented into the game, with the right analog stick being used to choose dialogue options. When conversing with certain NPCs, this is sometimes accompanied by a "Suspicion" meter, which is affected by the player's choices indicating how suspicious the character who Lucas is conversing with is., e.g. failing to give convincing answers when being interrogated by police. In these situations, if the player does not make a choice within the allotted time limit, the game will make a default choice for him, or else the conversation is abruptly ended. It should be noted that it is impossible to leave a conversation without the minimum amount of information necessary for the characters to progress in the game, and if one continually strays too far from the topic's intended resolution, the game will automatically make the choice for him. Examples include the cop in Joe's Diner telling the player, as Carla Valenti, about the waitress and the table at which Lucas was sitting, Lucas being interrogated by Carla or Tyler.
