Without getting too deep into RPG Theory, my favorite game, Alternity, would be considered a Simulation game. Like D&D, it models the world with a consistent set of rules that players use to interact with the fictional world. Simulationist games can be simple dungeon crawls up through political games where hardly a die is thrown. Depth of Story and Character varies depending on the table and can be as casual or intense as desired. In Simulationist games GMs put a lot of work into crafting an environment for the players to interact with.
Counter that with Narrativist games, like Blades in the Dark. The rules don’t simulate a world the players interact with, instead the rules facilitate the players telling the story. The role of the GM is toned down, they are not “in charge” of the world and the NPCs. Instead, the Players have input into what the characters encounter. In some games players take turns with narrating the events that occur, the twists the plots take and the situations the Characters find themselves in.
Think of it this way, the Characters are approaching a small Keep on the Borderlands:
Simulationist games would have the GM describe the scene (there are 3 guards outside looking through belongings as people enter the Keep), players ask for details, (How thorough are they searching?) then relate their plans and intent to the GM, (I’m going to cause a distraction so the others can sneak by) Then there might be some roleplaying between the distracting character and the guards.
In Narrativist games, the _players_ might decide that the Keep is on heightened alert, so there are guards outside looking through belongings, another might add that they have been on heightened alert for some time and are bored and inattentive. Another might add that one character distracts the guards while the others pass by with their weapons under their cloaks. Then there might be some roleplaying between the distracting character and the guards. The players switch back and forth between adding elements to the setting and adventure and roleplaying through the events. Narrative games have dice rolls to add that random element we all love so well. Usually there are more options than a binary pass/fail mechanic, often yielding results such as Yes and, Yes but, No but, and No and. These push the story forward and prompt GM and Players to improvise.
It might just be me being a grognard, but I enjoy my Simulationist games. I like the structure, be it as a player or GM. That said, the newer indie Narrativist games are enticing. Games like Legacy: Life Among the Ruins and other Powered by the Apocalypse style games come with loads of creative ideas and what looks to be interesting gameplay with the right group. Next convention I attend I’ll definitely seek some out.,
<<Yes, I’m aware that my use of Narrativist and Simulationist doesn’t necessarily agree with RPG theory. But I like the terms and think they work for my take on theory.>>