An interesting variation in branching dialogue, found in the game Culpa Innata, sees the player choosing one of several tactics at the beginning of the conversation. For example, while interviewing a potential witness in a crime, the player chooses to use either a formal, casual, or accusatory manner.
This decision affects the tone of the conversation, the options, and, ultimately, the information gleaned from the interviewee. Some tacts are more successful than others, and the player cannot immediately go back and try a different method. In order to approach the conversation differently, the player must come back another day.
The interface used by the player in branching dialogue varies significantly from game to game. The most obvious method is to present the player's possible responses word-for-word as his or her avatar would say them. The player has an infinite amount of time from which to make his decision, and the NPC gives his or her reaction as soon as the player makes his choice.
This is the case with most dating simulations and many western RPGs like Planescape: Torment. There is no ambiguity in the player's decision, but reading all the possible responses takes time and brings conversation flow to a halt.
While this is not necessarily a problem in games featuring dialogue presented entirely in text, modern games typically present all dialogue with full voice acting. As a result, the menu navigation and long pauses while the player chooses their next response can negatively impact immersion.
Games have attempted to address this issue by presenting responses in a different manner, or controlling the speed at which the player responds. In some cases, designers choose to present full responses alongside symbols or text that quickly sum up the general gist of the response.
An example of this technique can be seen in Desperate Housewives: The Game (Liquid Entertainment 2006). The game presents the player's options as a series of stylized faces depicting various emotions associated with the response, such as happy, sad, or angry. When the player moves their mouse over one of the faces, the full response appears in a text bubble for the player to read if they wish.
If the player knows they want to respond to a particular comment in a negative manner, they can quickly filter out the responses they do not want and just read the angry choices, thereby reducing the load on the player and speeding up dialogue to a more natural level.
One game notable for its aspirations for cinematic-quality dialogue scenes is Indigo Prophecy, which eliminates full responses entirely. The player sees his choices pared down to their essence, such as "Lie", "Avoid the question", or "Ask about murder weapon."
Once the player decides, his avatar delivers the full line related to the player's choice. In addition, the player has only a limited time in which to make a decision after the NPC finishes speaking. If the player fails to make a decision in that time, the game chooses a response for them, in a deliberate attempt to keep the conversation moving at a more natural pace.
Quantic Dream/Atari's Indigo Prophecy
The recent Mass Effect makes similar attempts at simplifying the presentation of the player's choices, but rather than limit the player's response time, it gives the player his options before the NPC finishes speaking. In this manner, the player makes his decision and the avatar delivers a response with little to no pause in the conversation.
Thus, both Indigo Prophecy and Mass Effect attempt to make conversations more natural by reducing the amount of time and effort the player spends considering their next response.
Although the heavily scripted nature of branching dialogue allows designers and writers to craft natural, flowing conversations, the limited nature of interactivity is very transparent to the player.
It is easy for players to see that they are simply choosing from paths laid out for them, rather than creating their own story. Further, players may be frustrated that they must follow such a straightforward path and cannot choose to inquire about certain topics. The Hub-and-Spokes Dialogue method addresses some of these problems.