Play in any game system long enough, and you’re going to want to tweak things a little – there’s something missing, or a rule doesn’t quite work the way you want it to. Or maybe you’re coming at things fresh with an idea of what you want to do. No game system matches your idea 1:1, but there are a few that come close enough that you don’t want to have to design a game from the ground up. Whether it’s just for a home game or you’re designing one yourself to publish, that means it’s time to change or ‘hack’ the system in question. But what thoughts might you want to have along the way? I’ve got three.

Now, these first two thoughts? Everyone in roleplaying games has them. Yes, everyone. Game designers? Certainly. Gamemasters? Even if they never make a single house rule (if that’s even possible), they take these steps when deciding which game they want to be running in the first place. Even players do them while designing their characters – in picking classes or stats or Talents or feats or Aspects or moves or whatever, they’re making mechanical choices in an effort to create a play experience they’ll enjoy.

So, if you’ve been around the block a few times you’re already an old hand at this process up to these two points, and if you’re relatively new, no worries, you’ll get plenty of practice. 

Thought #1: What Do You Want The Game To Do

This is the really basic step, there’s not too much to discuss here. What kind of stories do you want to tell? What genre? What power level should the characters be at? Traditional or lyrical? Solo or GMless or standard Gamemaster-and-players? What themes do you want to explore? All-ages, kid-focused, M-rated?

Once you at least have a rough idea, you can start to look into what sort of games, systems, options accommodate you, and start thinking about- 

Thought #2: What Rules Do You Need To Enable That (Or At Least Not Get In The Way)

At its most basic level, this thought is where you choose which game to play. That could also be where the process ends, barring changes that happen later at the table, because if what you wanted your game to do was let you play D&D, then you go ahead and play D&D! Things get a little more interesting when you’ve got a broad idea that a couple of games might cover, or a specific one that most games don’t cover at all. Sometimes this comes down to fiddling with the dials.

Sometimes the dial you need to turn is between similar but different games – perhaps you want to split the system? For an example you can read here, do you want to play a Star Wars game that doesn’t worry too much about all that Force stuff? Try Edge of the Empire or Age of Rebellion. Want a Star Wars game where the Dark Side can forever dominate your destiny? Try the old d6 version. Want to have a shot at telling a redemption story? Try Force and Destiny. 

Generic or universal games are typically designed with changing the rules in mind, with various dials you can turn to get to where you want. Want to play a Cortex campaign about superheroes, especially about the team dynamics that have made series like the Avengers and Justice League particularly engaging? Powers would be the obvious prime set to pick, but you taking a page out of the old Marvel Heroic Roleplaying game and picking Affiliations (Solo for the Punisher, Buddy for Rocket and Groot, Team for Captain America) is probably a good move. On the other hand, if you want the game to be less about team dynamics and more about what matters to the characters, maybe you’ll want to use Values (Glory, Justice, Truth, etc) instead.

However, what to do when a game off the shelf doesn’t quite get you to where you want, even after turning whatever dials it provides for you? Here’s where we start changing things. I suspect the most common house rule/hack, especially among larger and more traditional games, is simply to . . . not use a rule(set)/mechanic. One of the most common instances of this is Encumbrance rules in Ye Olde Dragon Game. Netrunning in Cyberpunk 2020? Absolutely not. Want a swashbuckling heroic adventure game? You probably don’t need a critical injuries/limb loss table. Want a game where the players have to solve things without violence? Don’t bother with combat rules (unless you want them to have the option, and then tell them they shouldn’t use it, that’s a different conversation).

Then we get to the point of needing to add something in that the base game doesn’t provide. Want your Luck in Cyberpunk RED to matter more than just a few points to add to a roll? Build a deck for it. Want to play with mecha in Genesys? You’ll have to figure out the stats for one on your own, or find a supplement to plug in. Don’t like Force and Destiny’s Morality system? Yoink it out, talk amongst your group, build a new system where it’s possible to walk the Path of the Bendu.’

From a designer’s perspective, let’s say your team liked the system behind Blades in the Dark but wants a military story about persevering through the horrors of a war against the undead instead of heists in a city full of ghosts. Band of Blades decided to add a morale score to the Forged in the Dark menu. Having done that, you need ways to have it go down (such as losing Legionnaires), and then a mechanic for it to go up (giving the troops leave, succeeding on certain missions). To make it more than just a shiny number, the morale score has to interact with some sort of mechanic – determining how many campaign actions the Legion can take.

Essentially, your choice of game or system, and what changes you make, should always be trying to support the kind of experience you want to have at the table.

With the universal considerations out of the way, let’s get to the hack-specific one.

Thought #3: How Will Changing The Rules Affect The Game

You might think the header for this section is wrapped up in Thought #2, and you’re not entirely wrong. Whatever sort of rules-adjustment you’re trying for, you’re obviously thinking about what it’s going to bring to the game – less bookkeeping, more grittiness, giant robots, more options, whatever. Perhaps another header for this section, then, would be “The Law of Unintended Game Design Consequences”.

Let’s revisit Encumbrance in D&D. Personally? I don’t like Encumbrance systems very much. Oh, sure, I can deal with simple ones – you have 7 points of load, and this Reinforced Hull costs 1, how would you like to spend the other 6 – because they’re really just there to keep characters from functioning like the TARDIS. You don’t have to do a lot of math or put in that much thought. But D&D 5E’s Encumbrance mechanics have decimal points, even the money takes up space, it’s all just way too much bookkeeping for me to deal with in most campaigns.

Except…

The last time Aaron ran a D&D game, he pitched it to us as a hexcrawl survival game, and the Encumbrance rules were in full effect. I was playing a bladesinger wizard, Strength was my dump stat, I literally could not even carry everything I got as part of character creation. I had to decide to ditch three days worth of rations to avoid being over encumbered. I was now out in the wilderness, with seven days to go until I started to starve to death.

But you know what? Having those rules in play worked for the game we wanted to play. We always felt like we were on the raggedy edge out there in the wilds, making tough and important choices. Found a bunch of treasure? Tucked the most valuable gemstones in our boots and buried the rest like the dwarves in The Hobbit, making a note on our maps in the faint hope that we’d get back here one day. A cart? Worth killing over. A ship full of pirates? We paid them to go legit so long as they helped haul stuff around for us. Finally reach a city? Suddenly my character’s Charisma becomes the most important stat in the party as we wheel and deal with bankers and black market dealers to get the best deals we can on supplies and equipment, because we know that we’re going to be depending on whatever we can get to survive for the next swathe of sessions.

No Encumbrance rules? That theme of struggling to survive with limited resources isn’t part of the campaign. There’s just noting to support it. Now if, while having Thought #1, none of that sort of thing seems very important you can ditch the Encumbrance rules altogether and nothing of value (to you) will be lost. If you were planning to ditch this mechanic from the system and the above does sound interesting, though, well, you might reconsider.

That’s a pretty simple example of how plugging and unplugging mechanics from the larger game can have an effect. Here’s another example, focused on what happens when you actually change the game, from my own experience. When we were designing Transit as a Powered by the Apocalypse game, we decided there would be two ‘halves’ of the character: one determined by what type of Artificial Intelligence you were, and one determined by what class of ship you were installed in and controlled. The mental side of stats (User Interface, Rampancy) would come from the AI, the physical side of stats (power, handling) would come from the ship. Most unique moves would come from the AI, but things like weapons and modifications would be chosen as part of the ship, and only the basics were already installed, leaving a lot of choice in the player’s hands. Each combination would also offer something unique, so a Combat Corvette and a Support Corvette would be tangibly different from one another. 

That design decision gave us a lot. It helped represent the duality of the characters that we wanted, beings of pure data given physical (exchangeable, replaceable) bodies to inhabit. It allowed us to achieve a granularity of detail that fit the setting – ‘chip-your-tooth-on-it-hard sci-fi’, as one reader put it. It also allowed us to  present players with 18 different character combinations in the core book, with further differentiation within each thanks to move and equipment choice, a lot more than most Powered by the Apocalypse games offer at the outset.

But we also gave up ‘the playbook’ as an ideal. Unlike Apocalypse World, Masks, Bluebeard’s Bride, Night Witches, etc., or their FitD cousins like Blades in the Dark and Band of Blades, I can’t hand a player a discrete Command Carrier playbook that’s on 1-2 pieces of paper, have them spend a minute or so circling or checking off a few options, and then be ready to play. First you need to go to the AI section of the book, then the ship one, then the crew one . . . probably a bit of flipping back and forth there too, as you figure out what combination of options you want and fill out the character sheet. The character sheet also can’t hold all of the options that a character will be able to choose from over the course of a campaign. So, unlike many PbtA games, a player is going to have to crack open the core rulebook as your character advances to pick out new moves at the very least.

Did we get what we wanted out of that design choice? Yes. Did we lose something that would appeal to potential play groups? Also yes. 

So that’s the heart of this final thought: don’t forget to think about what else your adjustments to a system will change, and then weigh those changes against what you want to accomplish.

If the cost is worth it to you, hack away.