Nonlinear gameplay

See also: Open world

A video game with nonlinear gameplay (sandbox style) presents players with challenges that can be completed in a number of different sequences. Each player sees only some of the challenges possible, and the same challenges may be played in a different order. A video game with linear gameplay will confront a player with a fixed sequence of challenges. Every player sees every challenge and sees them in the same order.

A nonlinear game will allow greater player freedom than a linear game. For example, a nonlinear game may permit multiple sequences to finish the game, a choice between paths to victory, or optional side-quests and subplots.

Some games feature both linear and nonlinear elements, and some games offer a sandbox mode that allows players to explore an open world game environment independently from the game's main objectives.

The genre began in the 8-bit era with games like TX-1 (1983), Mega Zone (1983), Elite (1984), Dragon Slayer (1984), The Battle-Road (1984), Brain Breaker (1985), Mercenary (1985), Metroid (1986), Dragon Quest (1986), The Legend of Zelda (1986), Cholo (1986), Darius (1986), Vampire Killer (1986) & Castlevania II: Simon's Quest (1987), Mega Man (1987), and The Goonies II (1987).

More recent examples include the Megami Tensei series (1987 to present), Fire Emblem series (1990 to present), Metal Max series (1991 to present), SaGa series (1992 to present), Ogre series (1993 to present), Sound Novels series (1994 to present), The Elder Scrolls series (1994 to present), Star Ocean series (1996 to present), 3D Mario games (1996 to present), Grand Theft Auto series (1997 to present), Fallout series (1997 to present), Banjo-Kazooie series (1998 to present), and Shenmue series (1999 to present).

A game that is significantly nonlinear is sometimes described as being open-ended or a sandbox, and is characterized by there being no "right way" of playing the game. A common consequence (intentional or unintentional) of open-ended gameplay is emergent gameplay.

Classification

Branching storylines

Games that employ linear stories are those where the player cannot change the story line or ending of the story. Most games use a linear structure, thus making them more similar to other fiction. Many games have offered premature endings should the player fail to meet an objective, but these are usually just interruptions in a player's progress rather than actual endings. More recently, many games have begun offering multiple endings to increase the dramatic impact of moral choices within the game, although early examples also exist. However, even in games with a linear story, players interact with the game world by performing a variety of actions along the way.

Still, some games have gone beyond small choices or special endings, offering a branching storyline that players may control at critical points in the game. Sometimes the player is given a choice of which branch of the plot to follow, while sometimes the path will be based on the player's success or failure at a specific challenge. For example, Black Isle Studios' Fallout series of role-playing video games features numerous quests where player actions dictate the outcome of the story behind the objectives. Players can eliminate in-game characters permanently from the virtual world should they choose to do so, and by doing so may actually alter the number and type of quests that become available to them as the game progresses. The effects of such decisions may not be immediate. Branches of the story may merge or split at different points in the game, but seldom allow backtracking. Some games even allow for different starting points, and one way this is done is through a character selection screen.

Despite experimenting with several nonlinear storytelling mechanisms in the 1990s, the game industry has largely returned to the practice of linear storytelling. Linear stories cost less time and money to develop, since there is only one fixed sequence of events and no major decisions to keep track of. For example, several games from the Wing Commander series offered a branching storyline, but eventually they were abandoned as too expensive. Nonlinear stories increase the chances for bugs or absurdities if they are not tested properly, although they do provide greater player freedom. Some players have also responded negatively to branching stories because it is hard and tedious for them to experience the "full value" of all the game's content. As a compromise between linear and branching stories, there are also games where stories split into branches and then fold back into a single storyline. In these stories, the plot will branch, but then converge upon some inevitable event. This is typically used in many graphic adventure games.

A truly nonlinear story would be written entirely by the actions of the player, and thus remains a difficult design challenge. As such, there is often no story in truly nonlinear games. Facade, a video game often categorized as an interactive drama, features many branching paths that are dictated by the user's text input based on the current situation, but there is still a set number of outcomes as a result of the inherent limitations of programming, and as such, is non-linear, but not entirely so.

Non-linear branching storylines are a common trend in visual novels, a subgenre of interactive fiction and adventure games. Visual novels frequently use multiple branching storylines to achieve multiple different endings, allowing non-linear freedom of choice along the way. Decision points within a visual novel often present players with the option of altering the course of events during the game, leading to many different possible outcomes. Visual novels are popular in East Asia, especially in Japan where they account for nearly 70% of personal computer games released there. A recent acclaimed example is 999: Nine Hours, Nine Persons, Nine Doors, where nearly every action and dialogue choice can lead to entirely new branching paths and endings. Each path only reveals certain aspects of the overall storyline and it is only after uncovering all the possible different paths and outcomes through multiple playthroughs that everything comes together to form a coherent well-written story.

Branching storylines are also often used in role-playing video games (RPGs) to an extent. A successful recent example is Bioware's Mass Effect, where the player's decisions have an impact on the gameplay. The game has a complex morality that is measured in Paragon and Renegade. A good action will not make up for an evil one; therefore, being nice occasionally will not stop people from fearing a killer or remove the reputation of an unsympathetic heel, but nor will the occasional brutal action significantly damage the reputation of an otherwise upstanding soldier.

Another RPG example is tri-Ace's Star Ocean series, where instead of having the storyline affected by moral alignments like in other role-playing games, it instead uses a relationship system inspired by dating sims, with its storyline affected by the friendship points and relationship points between each of the characters. Star Ocean: The Second Story in particular offered as many as 86 different endings, with each of the possible permutations to these endings numbering in the hundreds, setting a benchmark for the amount of outcomes possible for a video game in its time.

A unique take on the concept is Radiant Historia, a recent RPG released by Atlus. It combines non-linear branching storytelling with the concepts of time travel and parallel universes, expanding on the Chrono series. Radiant Historia takes it much further by giving players the freedom to travel backwards and forwards through a timeline to alter the course of history, with each of their choices and actions having a major impact on the timeline. The player can return to certain points in history and live through certain events again to make different choices and see different possible outcomes on the timeline. The player can also travel back and forth between two parallel timelines, and can obtain many possible parallel endings. The PSP version of Tactics Ogre featured a "World" system that allows players to revisit key plot points and make different choices to see how the story unfolds differently.

Nonlinear level design

A game level or world can be linear or nonlinear. In a game with linear levels, there is only one route that the player must take through the level. In games with nonlinear levels, players might have to revisit locations or choose from multiple paths to finish the level.

As with other game elements, linear level design is not absolute. While a nonlinear level can give the freedom to explore or backtrack, there can be a fixed sequence of challenges that a player must solve to complete the level. Even if a player must confront the challenges in a fixed sequence, they may be given the freedom to seek and identify these challenges without having them presented one after the other.

A more linear game requires a player to finish levels in a fixed sequence to win. The ability to skip, repeat, or choose between levels makes this type of game less linear. Super Mario Bros. is an early example of this, where the player had access to warp zones that skipped many levels of the game. Left 4 Dead 2 is a more advanced example of non-linear level design, featuring an A.I. structure that is capable of generating new level layouts on-the-fly according to each player's individual conditions. This makes it so that players are constantly experiencing a dynamic map layout, and as such may never follow the same exact path twice.

When a level is sufficiently large and open-ended, it may be described as an open world, or sandbox game. Open world game designs have existed in some form since the 1980s, such as the above-mentioned Elite, and often make use of procedural generation.

Sandbox mode

In a game with a sandbox mode, a player may turn off or ignore game objectives, or have unlimited access to items. This can open up possibilities that were not intended by the game designer. A sandbox mode is an option in otherwise goal-oriented games and should be distinguished from open-ended games with no objectives such as SimCity. Another popular Sandbox Mode based modification is Garry's Mod, also known as Gmod for Half Life 2. It has a variety of different uses, the main being the sandbox gamemode, allowing you to do whatever you want with everyday, normal items, or just have a firefight with your friends. The game is highly mod-able too. The "god mode" offered by many combat games and level editors effectively convert them into sandboxes, allowing the player to explore every nook and cranny of the game map without having to fend off enemies.

See also

• Massively multiplayer online games
• Multiple endings
• Open world