Note: this post is a response to Roguelike Radio’s episode on Simulation. It has caused me to evaluate the role of simulation in Justice, as well as to set guidelines for myself in order to help make decisions as to the relevance, importance and necessity of simulation in the game. It can deepen and enrich a game in ways that not much else can, or it can be a distraction, or worse, a never ending rabbit hole that graveyards a project.

Simulation in games can create a deeper sense of immersion, help cushion the suspension of disbelief, lead to emergent behavior when systems interact, provide a wider and more complex world within which the gameplay takes place and much more. When coupled with the procedural generation of things like terrain, history, culture, NPCs, and items, simulation takes on an unpredictable and often fascinating and exiting aspect.

Simulation can also be a gigantic rabit hole that detracts from gameplay, and sometimes, especially in the roguelike genre, it can kill a game. The Rabit Hole of No Return. I myself have felt this temptation, because it can be so awesome to see your simulation playing out and interacting with itself…but there comes a point when you are no longer building a game, you’re building a simulation, and the end is nowhere in sight. When this happens, projects disappear.

I do not want this to happen to Justice, and I want to stay focused on building a game. So, these are my thoughts on simulation, but they are also my rules for myself; when I find myself getting into the weeds of simulation, I will ask myself if what I’m doing adhere’s to this, and if it doesn’t I need to either scrap it, or go with a simplified solution.

1. Simulation + PCG improves replayability

The simulation + PCG combo is a powerful one. PCG means that every game is going to be unexpected and new. The deeper that goes, the richer every play. Even a little simulation (monster AI in the classic roguelikes for instance) goes a very long way. Simulation should make things more fun by giving the player complex systems to interact with that behave in unexpected ways due to the PCG. If it’s not making things more fun (and fun can include simply watching fun things happen), maybe I should be working on something else.

2. Simulation creates the “window effect”

J.R.R. Tolkein mentioned in a letter to a friend, or a forward to the Silmarillion (I can’t remember which) that he wanted his readers to feel like they were looking upon Middle Earth through a window; that the events taking place and the characters involved felt like they belonged to something much, much larger. I feel like Tolkein accomplished this in his works wonderfully, and he did so by extensive, loving work on his fictional world. The reason so many works are able to be posthumously published by Tolkein is because he had written so prolifically on the world of Middle Earth that entire books have been able to be assembled from his notes and papers on his world and its lore.

I want the simulation in Justice to provide this same “window effect.” The player is participating in a world that is larger than him/herself, and there is a certain sense of mystery to the goings on of the city. An NPC may rob a bank, but there should be a reason behind it, and this shouldn’t be immediately obvious to the player. It could be a part of a grander plan that an unknown super villain is concocting. A mugger could attack a civilian for no apparent reason, but if the hero were to follow the mugger, they might discover that it was a hit for a mob boss, or a desperate move in order to get money to pay a drug-dealer, who in turn may have a small organization of cronies, or who may have connections with a crime lord of the city. A police dispatch may just let some robbers get away, but this is because they are paid off by a villain, or by a corrupt politician.

3. Simulation helps alleviate the suspension of disbelief

This is a smaller issue for me, but the closer that a game gets to “real life” (e.g., it has a modern setting…such as a modern-day city…), the more that our internal “scripts” kick in and we start to evaluate things on its “believability.” Simulation will be more important in a game like Justice than in more traditional fantasy roguelikes or even sci-fi roguelikes because in those games, the player is asked to accept a much larger set of “rules” for how the world works that are not like ours, and so it’s easier for players to accept strange things in these events. For instance, in your typical fantasy setting, people don’t often ask things like “where does magic come from?” or “how did dwarves come into existence?” because so much of the world is alien to our own. However, when presented with a setting that is exactly like our world, except that certain people have super powers, questions like “how did they get their super powers?” arise almost immediately.

4. Simulation provides emergant behavior

A monster that attacks me is sort of interesting. A moster that attacks me intelligently is pretty interesting. A monster that attacks other monsters intelligently is both interesting and provides strategic decisions. Two monsters that attack each other and me, intelligently, based on systems that I can manipulate, the ramifications of which will affect other systems is on a completely different level and falls into the category of emergant behavior. ‘Justice’ is about this interplay between corruption, the justice system, NPCs that make decisions based on PCG and these systems, and the player’s own invovlement in these systems. This emergant behavior supports the other reasons for simulation extremely well.

Summary

Simulation should improve replayability, create a “window effect”, alleviate the suspension of disbelief create emergant behavior, and if an aspect of simulation is not accomplishing these things, I should question whether or not it belongs in the game. I may think of other reasons, but I think this a great place to start, and supplies me with a good framework for making development decisions.