Focused on player behavior, in GNS theory participants in role-playing games organize their interactions around three categories of engagement: Gamism, Narrativism and Simulation.
[1] In his article "System Does Matter",[3] which was first posted to the website Gaming Outpost in July 1999,[1] Ron Edwards wrote that all RPG players have one of three mutually-exclusive perspectives.
Revisiting character motives or underlying emotional themes often leads to escalation: asking variations of the same "question" at higher intensity levels.
Many simulationist RPGs encourage illusionism (manipulation of in-game probability and environmental data to point to predefined conclusions) to create a story.
Combat may be broken down into discrete, semi-randomised steps for modeling attack skill, weapon weight, defense checks, armor, body parts and damage potential.
Some simulationist RPGs explore different aspects of their source material, and may have no concern for realism; Toon, for example, emulates cartoon hijinks.
[11] To disprove this, Gleichman cites a survey conducted by Wizards of the Coast in 1999,[12] which identified four player types and eight "core values" (instead of the three predicted by the GNS theory) and found that these are neither exclusive, nor strongly correlated with particular game systems.
[8] Gleichman also states that just as the Threefold Model (developed by self-identified Simulationists who "didn't really understand any other style of player besides their own"[14]) "uplifted" Simulation, Edwards' GNS theory "trumpets" its definition of Narrativism.
[15] Lastly, Gleichman states that most games rooted in the GNS theory, e.g. My Life with Master and Dogs in the Vineyard, "actually failed to support Narrativism as a whole, instead focusing on a single Narrativist theme", and have had no commercial success.
[16] Fantasy author and Legend of the Five Rings contributor Marie Brennan reviews the GNS theory in the eponymous chapter of her 2017 non-fiction book Dice Tales.
While she finds many of its "elaborations and add-ons that accreted over the years... less than useful", she suggests that the "core concepts of GNS can be helpful in elucidating some aspects of [RPGs], ranging from game design to the disputes that arise between players".