Non linear stories in games are stories that has more than one possible way of happening. Most often the story changes as a result of player actions, but randomly generated stories as possible as well. can make a game a lot of fun. When a player can change the story, this can be done either by allowing the player to make a choice, or having the story change based on how the player performs or what they do. The difference between a player choosing an outcome rather than what the player does is that a choice generally implies control over the action, while what a player does could be an unintentional choice on behalf of the player, such as walking into the wrong room without knowing. Changing the story based on how the player performs is more often about changing the story based on how long it takes the player to accomplish a goal, or whether or not they accomplish it.
Non linear stories offer something that other types of media generally cannot do, at least not easily. Some books allow you to make a choice and turn to a page to see the result to keep reading on, and some films offer alternative endings as an extra feature, but otherwise most stories are linear.
Linearity, Agency and Choices, and Characters
While games benefit from this type of story, it has a major problem. Non linear stories are fun, but they are not necessarily great stories. Even if the choices you made result in a well written story that makes sense, the story necessarily loses credibility and any sense of being naturally cohesive. The actions that the player took are only technically the actions that the characters took, and hence the characters in the story lack agency. It is no longer the actions of the protagonist that lead to the resolution of the story, but the whim of the player, which makes the ending arbitrary rather than meaningful.
This does not mean that a story with player choices is bad, but the lack of agency and meaning are a definite flaw. The more a character’s choices are left to the player, the more that character just becomes a puppet with less personality and agency. This could be taken to the extreme where the character is simply the player, and no attributes or actions are left for the character other than those the player chooses. In this situation the issue with the character being a puppet becomes less important because the character is essentially the player, so there is no expectation or appearance for the character to have depth like in a linear story. For example, Shepard in Mass Effect can have whatever appearance you like and will make the choices the player wants, but there is still the standard appearance of Shepard that everyone knows and that is in the cinematics, and he still uses words and has a voice that the player did not choose. Shepard is essentially half a character and half puppet, as opposed to Dragon Age and Fallout characters who are generally not even named or voiced because they are entirely puppets, and they have many more dialogue options that are used literally, instead of Mass Effect’s dialogue options which give you the general idea of what Shepard will say. This is why characters like Shepard are talked about in similar contexts to Master Chief from Halo, there are only so many versions of Shepard which people can easily discuss with each other, while fully customisable characters are much more difficult to consider iconic or memorable and cannot really be discussed other than by describing it to others.
This does not make Shepard a bad character, it just makes him appear as a real character who is unfortunately half puppet. This compromise is often intentional for game designers who want to make the player character more recognisable and to give them more character, but this can be seen as not being as good as a full character or a full puppet. Regardless, a linear character, a puppet, or something in between are all valid options with different qualities and advantages.
Gameplay and Story
Linear stories are better suited to storytelling because the characters in it are interesting and have their own history and make their own choices. Non linear stories are a great gameplay element, but not necessarily as good of a story element. It is difficult to tell a story when you don’t know what the player will do, and the player might very well undermine the themes that the game designer wants to include, or they might choose not to go somewhere that they want them to go to for important parts of the story. The game designer can limit the player to have to do certain things so they can implement themes or story elements, but this is dangerous as it limits the player’s freedom and therefore the non-linearity of the story, which depends on player choices. Doing so might break the illusion of control the player had or force them to do something they do not want to, which they might not like.
The fact that games are inherently interactive does not mean that games should have interactive stories as well. Games are a medium in which we can have fun and tell stories, and non linear stories have many flaws as we have seen. To say that games are better with non linear stories does not make any sense, as it severely limits the potential of games to deliver stories and themes and characterisation, as well as limits what game developers can do and what kinds of games the players want to play. This idea is essentially analogous to the naturalistic fallacy, claiming that the nature of games is interactivity, therefore more interactivity is always good. Linear and non linear stories are both fun, useful, valid, and good and bad in different ways.
Both linear and non linear stories work in various games.