3 Ways To Modify Any Game

​My earliest RPG experiences were with D&D 3.5e, 4e, and Pathfinder. These games are known for being “crunchy” (having many complex game mechanics), and 3.5e in particular was known for having a glut of supplemental materials of dubious quality. With these games, because of the breadth and depth of mechanics and the focus on tactical combat, supplemental materials often negatively impacted game balance, and that had a chilling effect on my perception towards homebrew or 3rd-party published content (materials not produced by Wizards of the Coast). Over the years I’ve moved away from those kinds of games, and towards more rules-light games like FATE, Cypher, and OSR (D&D 2e or earlier, or modern games built with a similar design philosophy or shared mechanics). One thing that I’ve found so refreshing and rewarding about these systems is how easy it is to modify the games to suit your needs, without having to worry too much about negatively impacting game balance. With some consideration, these modifications could even work for a medium-crunch game like D&D 5e. Here are 3 ways to modify games. Treat these as ways to think more about why the mechanics of a game exist, and how changing them affects game balance and the play experience, so that you can come up with your own modifications!

1) Power Points
Here I’m using power points to refer to any kind of system where players gain points for their actions, which can later be spent to affect future actions. These are often employed in “narrative” games, as with the fate points in FATE, to encourage players to roleplay and to interact with the world in a way that drives the plot forward. However, I think this system can be used for several other purposes, such as to fill “holes” in character builds, to bring a little cinematic flare to medium crunch tactical combat games, or even evoke unique themes.

I ran a campaign in my Phantasmos campaign setting using Numenera as the game system. The Phantasmos setting has various species and classes of its own, not all of which mapped cleanly to the options available in Numenera RAW (rules as written). Let’s use Arpaia the dogu apoptomancer as an example. Dogu are a species with several unique abilities such as shifting between a humanoid and monstrous form, and a sense of hyper-touch, and apoptomancers are a character class focused on the manipulation of controlled cell-death and the neuro-immune system to induce metamorphoses. Rather than constricting the player to a limited set of descriptors (like species) and foci (like feats) that reflect all of these varying and specific abilities, we had him train in the skills “dogu senses” and “apoptomancy,” which he could use to do things that his character should be able to do, but aren’t strictly built into his RAW character sheet. Importantly, if he were to use these skills in any way on a scale of power or utility comparable to his actual RAW special abilities, he would have to spend power points. Not only does this give him greater flexibility in character building and ensures that he can always do the things he should realistically be able to do, this encourages creative thinking and interactivity with the story to get power points and leverage his abilities.

A final note on power points: The game Tenra Bansho Zero has a really cool karma system, which is used both for character building and as power points. However, in that game, as you acquire more karma, you become increasingly likely to turn into an ashura, a demon. The point of the game is in-line with the Buddhist philosophy of separating oneself from material attachment (as expressed by resolving karma). The strengths and weaknesses of material attachment, the Buddhist themes of the setting, are actually instantiated within the game mechanics using power points!

2) Change The Dice
So this gets into probability theory, which really should be a whole post in its own right, but I’ll go over some basics here. While many games use a d20 for action resolution as a matter of convention, I think most good games are mindful of their dice. A d20 is a very different beast than a 3d6 or FATE dice system, and understanding these differences can radically change how a game “feels.” Note that I will not be discussing games which use dice pools here, as the probabilities get a bit more complex, and I think that would be better suited for its own post.

A d20 is a uniform distribution, meaning there is an equal probability of rolling any value, which from a range of 1 to 20 means 5%. The wide range and uniform distribution are why people often describe d20 as being “swingy,” meaning it is common to roll excessively high or low.

A 3d6 is a normal distribution, or bell curve, meaning that you are most likely to roll the mean, and the further from the mean a given value is, the less likely you are to roll that value. With a range from 3 (rolling [1,1,1]) to 18 (rolling [6,6,6]), 25% of the time you will roll a 10 or 11 (27 ways each to roll a 10 or 11) , whereas you will only roll a 3 or 18 <0.5% of the time each (because, as already stated, there is only one way to roll a 3 or an 18). This is why 3d6 is less swingy; most of the time you will roll somewhere near the middle of the distribution.

So despite the fact that these dice mechanics have very similar ranges, they have very different probabilities. I’ve already explained how this affects swinginess, but it also affects the impact of modifiers. Unlike a swingy d20, with 3d6, assuming a difficulty of 10 or 11, you’re more likely to narrowly miss or succeed, so the impact of a small modifier is greater. For example, normally you would have a 62.5% probability of rolling a 10 or greater. However, with a modifier of +1, the range is now 4 to 19, but the dice remain the same, so essentially you’re sliding the distribution up by 1. In other words, because a roll of 9 now gives you a value of 10 (roll+1), and there’s an 11.6% probability of rolling a 9, you can add that to the 62.5% for a 74.1% probability of rolling 10 or greater. With a d20, that +1 only nets you an increase of 5%! That being said, for d20, no matter how many modifiers you have, each nets you +5% towards a higher value, whereas with 3d6, because the probability of a given roll gets lower the further you go from the mean, higher modifiers give you diminishing returns.

It may help to think about weapons. In Dungeons & Dragons, a greataxe has a damage roll of 1d12, a uniform distribution comparable to a d20. Greatswords have 2d6 damage dice, a normal distribution. They average about the same; minor quibbles aside they are roughly equal in power, but they behave differently, and in a way that reflects a specific intention. Compared to the greataxe, the greatsword will be more reliable, it will generally deal about 6 damage, only occasionally doing exceptionally more or less. The greataxe will average about the same, but will swing wildly from very little damage, to very high damage.

Keep in mind that these dice distributions also affect character progression and relative power. In a game where dice modifiers improve over time (such as by leveling up), there will be a much larger difference between lower level characters in a 3d6 system than a d20 system, but a much larger difference between higher level characters in a d20 system than a 3d6 system. All of this is to say that dice matter!

There is so much more I could say about probabilities, but as a last aside, keep in mind that the range of values on a die also matter. For instance, for FATE dice, you roll 4 dice, each with two negatives, two neutrals, and two positives, meaning you have a normal distribution centered at 0. Because the range extends into the negatives, is a relatively narrow range of -4 to 4, and is centered at 0, the impact of a modifier will in general be much larger than a 3d6 system, where the range is much larger and entirely positive.

All of this is to say, if you understand how these distributions affect your game, you can substitute them safely. If you want to play D&D 5e where the game is less swingy, and where characters become significantly more powerful from level-to-level at lower levels, but there is less of a power curve at higher levels, just substitute your d20 for 3d6!

3) Combat Modifiers
Obviously not every game is about combat, or treats combat to varying degrees of abstraction, but even so, many games deal with combat, and often not well. Personally, I’ve always felt like coming up with tactical character builds in crunchier games is fun, and the idea of combat is fun, but in practice it often gets bogged down. Either the game is so crunchy that it’s slow and cumbersome, or the game is so light that it becomes rote and stale. However, there are some simple ways to make combat faster or more fun, without fundamentally altering the game!

The easiest thing is to abstract. As the GM, try to apply narrative flourishes to the enemies’ actions. Describe how they attack, how they defend, how they behave in response to the players (even if it’s just a matter of taunts or sneers or wide-eyed looks of apprehension). Encourage the players to do likewise. Regardless of what spell/ability/move they do, let them have fun with how they describe the flavor of that action. A “missed” attack is much more satisfying when it’s described as a sure strike that was deftly parried, or glinted off the enemy’s armor. This can be difficult to do at first, but the more you practice, the more natural it will become.

In terms of mechanics, one option is an escalation die. One way to implement the escalation die would be to have a d6 appear at the beginning of the second round facing 1, and increase the number each round, up to 6. All combatants gain the value of the escalation die to their attack bonus, so that as combat progresses, all combatants are more likely to hit, making the game deadlier. This creates tension, it makes weaker enemies potentially more dangerous if in large enough numbers, and it moves combat along quickly and in a satisfying way. This kind of modifier could be applied as a random roll instead, reflecting the randomness and deadliness of real combat, or could be set to a specific value as a way to signify the stakes of a given encounter. An alternative way to do an encounter die would be to have the die lower AC, increase the damage roll rather than the attack roll, or give the defender a counter-attack chance (x or lower on a d6 allows counter-attack / attack of opportunity, where x is the value of the escalation die), or activate special abilities from the enemy or evoke some other “event”, such as more enemies arriving or a change in the environment. In addition to affecting the flow of combat, these alternative options can also have fun narrative implications.

Manipulating quantities of enemies and action economy is another useful combat modification, especially for mass combat or “boss fights.” Hordes of weaker enemies may seem cool at first, but either they’re too weak, in which case they’re ineffectual and their turns are a boring waste of time, or they’re just powerful enough that through sheer number of actions they can overwhelm the players in a way that is also unsatisfying. Instead, by clumping these weaker enemies into a smaller number of more powerful swarms, the encounter can be faster and more engaging. Even quicker, one could make the entire swarm a single entity with multiple actions. Likewise, rather than defaulting to giving a “boss” enemy a swarm of underlings to balance the action economy, an especially big-bad could get multiple actions per turn, or for a literally big-bad like a kaiju, its body parts could be treated as separate entities.

These are all intentionally loose and system-neutral, to show how you can go about thinking of any game. Crunchier games will be harder to modify without accidentally creating imbalances or “breaking” the game in other ways, but even those games can be modified if you carefully consider what affects the modifications will have. Modifications can affect how a player perceives an encounter, how they build their characters, the balance of the game, and the flow of combat, and any number of other things. If you understand the game and understand what you and your players want, then you don’t have to be afraid of modifications!

Max Cantor is a former cognitive neuroscientist and soon to be data engineer, whose love of all things science fiction, fantasy, and weird has inspired him to build worlds. He writes a blog called Weird & Wonderful Worlds and hopes people will use or be inspired by his ideas!

Picture Reference: https://tvtropes.org/pmwiki/pmwiki.php/Main/MadScientist