RPG design (with explosions!)

To me, the most fundamental element of game design is the “core game loop:” the most common adventure cycle you want your players to go through. In D&D it is “get quest, go to location, engage in combat, receive loot.” The majority of D&D’s mechanics are about supporting that loop.

So if you’re designing a new system, the first question I ask is “what is your loop?” or more generally “on a typical session, what rolls might you ask your players to make, or activities would you expect them to do?” Players solve problems with the most powerful mechanics available to them: if the whole game’s ruleset is about combat, then that’s what most players are going to use to solve their problems—and the kind of problems GMs give those players are probably going to be solvable by combat: after all, if you have a Rogue, a Barbarian, and Bard, sure, one of them can talk their way out of problems, but if you don’t let your players fight at least some of the time, the Barbarian will be like “why am I even here.”

A second, related question is “what kind of story do I want to tell?” In your thread, you talk about superpowers that grow progressively more dangerous as you use them. So there’s one question, “how do I represent that mechanically?” and there are examples all across RPGs, from Overlight to Vampire the Masquerade to the Wild Magic Sorcerer in D&D. Collect a bunch of them, and note the ways they do and don’t approximate the feel you’re going for. We’ll get back to them later.

But the other question is “how is that mechanic going to tie into the GM’s story?” because mechanics and concepts don’t live in isolation, but as part of a greater design ecosystem. That single mechanic has to live in a whole game—a game with a core loop.

My favorite way to design this is by modeling after media examples: not only does that give me a clear template in my head, but the more a story trope is easy to recognize, the better the chance that the GMs running your game will understand what you’re trying to do and be able to make that happen at their own tables. I’m a sucker for the trope of the superhero nova* who gets so powerful that they’re about to destroy all the things and become a monster, but then, when all seems lost, their friends are like “Jean! Remember who you are!” And then the Nova remembers and calms down and the day is saved. I’m gonna design that! This isn’t going to be what you’re looking for, but it’s an example design process.

So now I know what, story-wise, my game is about: a game of superheroes where their powers grow more dangerous as they use them, but their connections to their friends/fellow supers save them from destruction and remind them of their humanity.

And because I know what my story is about, I also have my design to-do list: I’ve got to make sure that the players do use their powers—rather than avoid using them because they’re dangerous, which is a thing risk-averse players might try to do—and that the powers become more dangerous over time, but also create that social connection that’ll save them.

How do I want to make the player use dangerous powers? Let me look at my media example: superheroes use their powers because their foes are really powerful and only superpowers can stop them. So I’m going to make mundane actions pretty weak sauce, but superhero abilities the default if you actually want to get shit done—this is a good example of how balance plays into game design on the creative level, rather than just the numbers-level. Now, the supers have to use their powers if they want to save the day, even if their powers are getting more and more unstable.

Now how do I model the instability? This is a superhero genre, so I don’t want to compel them to use their powers the way vampires are compelled to feed, but I do like the way Hunger dice in Vampire kinda build up over time. But unlike vampires, I’m not going to have any way for the PC to ratchet their own powers back down, like vamps do by feeding. The only way they’re going to reduce their Power Instability is by other players using that social connection thing. Oh right, now I have to figure out that part, don’t I...?

I remember Monsterhearts RPG, which has a mechanic called Strings—those are great for social connections! In that game it’s mostly about flirting, but I abstract out the basic principle the mechanic is going for: the players have a social scene, one player rolls, and if they succeed, then they get to carry forward a String to be used on that character later. Players grab tons of Strings on each other, which is exactly what we’d need for that big climactic “Remember who you are!” moment.

At this point, we can see the skeleton of a game design coming together, and most importantly, I can see the core game loop from here:
-Players do scenework and at the end of the scene, they roll to get Good Memories/Strings for each other. This is probably a “hanging out in their secret base” vibe, which fits nicely with the superhero media examples I’m trying to approximate
-Then players find out there’s a villain/disaster/other/obstacle out there, and the players have leave their base and to go fight them with their superpowers. They’ll probably have a “use your powers” ability and every time they crit, their power grows and they get closer to some kind of threshold where they’ll explode or whatever
-If a player using their powers hit the Nova Threshold during the encounter, then a fellow player spends Good Memories to bring them back from the brink

Now I know my players are going to buy into this core loop in part because I’m keeping my mechanics pretty limited: if they want to solve problems, their powers are their only real option, and if they want to not explode, they better make sure their friends have Good Memories with them. But even so, I have to double check my incentive structure: am I rewarding players for doing what I want them to do? It’s important that whatever I’m using for rewards will reinforce the core game loop:** maybe character advancement/XP is tied, not to defeating the villain, but to spending Good Memories to help their fellow players. Now my players are even more incentivized to bring their fellow players back from the brink rather than let them explode, so I can reasonably expect a lot of scenework.

From here, I’m going to keep refining the incentive structure—do I want all the players spamming their Good Memories at once because they all want XP, or do I make it a rule that you can only do it with one player per Nova Threshold incident? Does character advancement make players better at spending Good Memories to lower Power Instability (and reflect the growing closeness of the group)? Does it slow the rate of Power Instability (nahhhhhh! Keep it explosive!). What if advancement increases the amount of Power and Instability before you hit the Nova Threshold? That means that a character will take longer to explode, but they might be catastrophically powerful when they go critical! I decide that fits with the theme of the game I’m going for and raises the stakes nicely, but I like the idea of having multiple different ways to advance: maybe some characters get better at talking their friends down, while others become both more powerful and more dangerous.

As you can see, there’s a ton of game design that I’m doing before I ever get to a dice mechanic or hard-and-fast rules. If I were building this into a real RPG, I’d probably be modeling it on Powered by the Apocalypse: not only am I drawing inspiration heavily from other PbtA systems, but PbtA only allows a finite set of specified actions, and that works with my whole “making the supers use their powers by making it their best/only option” approach. I’ll create playbooks for different personality/power types/tropes and figure out how to integrate my unique mechanics (Good Memories, Power Instability, and Nova Threshold) into a PbtA template. I’m going to wind up with something that’s kinda like Masks, kinda like Monsterhearts, borrowing some concepts but no concrete mechanics from VtM, and all of the mechanics will support the core game loop and kind of story I want to tell. Eventually I’ll playtest it, both for mechanical balance, game-feel (is it frustrating? are all the players constantly hitting their threshold at the same time?). As I playtest, I make sure that my incentive structure follows the core game loop, and that I’ve given the GMs enough tools to facilitate that loop and tell interesting stories with it.

So that’s one example of how to approach RPG design! I like it because it keeps me focused on why I am making this game, and the ways it is or isn’t different from other RPGs (the more RPGs you’ve read, the more ideas you can borrow from, even ones that don’t seem to resemble your idea at all). Sometimes you’ll find that another RPG is doing the thing you’re going for, or it’s so close that you can hack in a homebrew rule or two and be good to go—THIS IS AN EXCELLENT OUTCOME! It saves you hours and hours of design effort and you can just go and play the thing. But by focusing on what you want out of your game (your “design pillars,” the elements you can’t live without), you know that if you are designing something yourself, it’s because it genuinely doesn’t exist yet.

Hope all of that is helpful!

*Nova is a term I’m borrowing from a Masks playbook; they’re meant to be characters like Jean Grey, which is a lot like what I’m going for here.

**In D&D, you get loot, and that loot usually helps you in combat. Even if you just get gold, usually what you spend it on will be a magic weapon or object that will help you with combat! You also get XP that makes you better at, well, combat! Maybe a diamond that your healer spends on resurrections so you can get up and go back to doing combat! The reward feeds the loop.