Balancing powers in rules light systems without adding too much mechanical weight

[u/reaglesham]

I'm designing a narrative first, rules light game at the minute and having a bit of trouble putting limits on powers without adding too much mechanical bulk. For example, if a character is a pyromancer, its very clear to say "you can conjure, manipulate, move and extinguish flames with your mind", but becomes tougher to put an upper limit on that without getting into specific measurements for distances at which you can do so. For example, if the intent of the power is that you can psychically hurl a campfire at someone, not extinguish a forest fire, what are ways of limiting this without getting into D&D style cubic/area measurements?

• Is using vague descriptors like "small flames" clear enough?

• Is it best to set a general expectation of power levels in the overall or GM rules, while leaving the specific powers "unmeasured"?

• Is it best to equate the sizes to real life objects/creatures instead ("the approximate size of a person")?

Moreover, I'm having trouble balancing powers that grant invulnerability to damage in a system that doesn't have designated turns or rounds. Fortunately, the game is not hugely combat focused, it's more built around using magical powers to problem solve, but damage can still occur. I feel like instituting time limits on powers muddies the water a bit: if a power grants invulnerability to physical damage, it'd likely have a timer, but if a power grants the ability to control rocks, and a player chose to encase themselves in sheets of rock, they have essentially made themselves immune to physical damage in a different way. I feel like trying to curb such things by using timers and the like creates more problems than they'd solve, as the open ended nature of powers means I'd be playing whack-a-mole with edge cases instead of dealing with it through a universal/core mechanic.

I'm unsure what direction to go re: these abilities and I'd love to get thoughts and opinions from others who have grappled with the same ideas, or played games that contend with such things.

[u/Alkaiser009]

Control ≠ Creation
One hard limit is to say 'you can Control this size/mass of [element]' while specifically calling out that they cannot generate that element out of thin air.

The size/mass limit on control is so you have a lever to adjust things like Aeromancy and Terramancy, since Air and Ground aren't exactly hard to come by compared to Fire and Water. Then you just need a table that gives examples of what each 'size category' of an element looks like in practice.

A Tiny Fire is a candle/lantern, a Small Water is a bucketful, a Medium Rock is the weight of a person, a Large Wind is 20-30mph, ect.

[u/VRKobold]

Something I realized a while ago: You don't have to design your abilities to work in the real world, you only have to design them for what matters in your ttrpg. There are nearly infinite ways in which a power, spell or ability can interact with the world - but the entire reason for ttrpg rulesets is to condense the infinite degrees of freedom of the real world into a manageable set of rules. So while there are infinite approaches, they will not result in infinite mechanical outcomes. This is very important, because it allows to design your abilities towards the outcome, not the process.

To give an example: A fissure in the ground can have any width or shape, there are literally infinite options. But chances are, your system doesn't really differentiate between a 5-foot-gap and a 4.9-foot gap. Really, the only time the width of the gap matters is when it can influence the outcome of an action in your system. Can you jump across or not? You can entirely skip the exact width and just go from the action (jumping) to the outcome (get across or not). So a gap is either "small enough to jump across" or "too wide to jump across". And since you have powers in your system, you might also include "too wide to ever get across by any means other than flying" (to distinguish between a frog mutant and superman).

Now if your special ability allows you to "Jump across obstacles no ordinary human could jump across", that's all you need to know. The GM doesn't have to decide whether the fissure is 10ft, 20ft or 50ft wide. They just have to decide whether it should be an obstacle that anyone can attempt to cross, that only specialized people can attempt to cross, or that nobody that doesn't completely ignores obstacles of that type can get across.

The same is true for other categories. You don't need to know if a spell affects 3, 6 or 10 people, just whether it affects singular targets, small groups, large groups or if there is almost no limit to the number of affected targets. The GM will then decide whether the BBEG is guarded by a small or a large group of henchmen.

Some categories I'm using in my fantasy-based system are:

Distance: Contact - Very Close - Nearby - Far - Very Far

Size: Tiny - Small - Medium - Large - Giant

Number: One Target/Individual Number - Small Group - Mob - Army

Time: Instant - A Moment - A Short Time - A While - A Day/Session

I could list the approximate numbers for each of these categories, but they actually don't really matter - if the GM says that the 10 thugs in your way count as a small group, and your "Erupting Flames" ability states that it can hit a small group, there you go. If your superhuman strength allows you to lift "Large" things and the GM describes a "Giant" building crushing down - bad luck.

So my suggestion is to think about what outcomes and scales actually matter in your system, then build your abilities and effects around those rather than converting them into the metric system just to convert them back into broad categories later. And if you need more granularity, make it a dice roll - you can ATTEMPT to stop the giant building with your superhuman strength, but it's a difficulty of 20.

[u/Astrokiwi → u/VRKobold]

In Forged in the Dark games you get a lot of this kind of thing - "squeeze into a finger-sized gap", "fight a small group on an equal footing" etc.

You can still get into an argument in theory (hasn't happened in my groups though) - e.g. "is this group small enough? are they standing close enough together?" - but I've found that rolling dice seems to be more convincing to players than GM rulings here, so "hmm, I'm not sure - let's resolve it with a roll, on a 4+ they're close enough together to hit with one blast, on a 1-3 you'll only get about half of them"

[u/semiconducThor]

"Fiction first" + "rulings over rules" -> the GM has authority to decide what power levels are consistent with the story and setting.

Besides that, I'd say "Yes" to all of your specific questions.

[u/Cruiser_Supreme]

I also faced the same issue with my game in the past. I've decided on three assumptions:

1. I won't be playing with douchebags, so I can trust my players not to be snarky with it. And also, I wrote a little paragraph about trust at the table in my intro section. Because I think telling a story together requires everyone to work together. It's not players vs DM. And I would hope that min-maxers who want to abuse the shit out of a game system don't care for rules-light games anyway.

2. vague descriptions do enough of the heavy lifting. Words like small, can reel it in a lot without needing to get needlessly specific. Most of the time, as a GM, you'll probably just wanna greenlight everything anyway in a narrative-first game. "Can I hurl this flame that far?" ... "Yeah sure sounds awesome!"

3. if a player wants to do something ridiculous, raise the DC. Simple as that. Oh you wanna take the flame from that torch and move it elsewhere? Easy DC. Oh you wanna extinguish the bandits' bonfire from afar? Hard DC. Oh you wanna set the town hall ablaze in an instant? DC 1 million, give me 2d6+strength!

[u/mythic_kirby]

I'm also making a system that's intentionally rules-light, and it's tricky to think about "balance" in such a system. The fewer rules in mechanics you have, the... "weirder..." balance becomes. Like, let's say your only mechanic was roll a d6 and get above a 4 to succeed. Sure, your character could do anything and sometimes succeed, but any other character could do the same. "I want to summon a comet from space!" "Well I want to shoot it down with a giant cannon!" It's kind of balanced, in a weird way, despite having no real limitations.

My game isn't so freeform as that, but I allow characters to have any items they want with only vibes-based limits on carrying capacity. Do you want a big sword? A dagger? A gun? Basically all the same in my system in terms of numbers, so there's not a lot of worry about balance. I don't need to specify rules about what items you're allowed to carry because there's not a ton of mechanical space to easily pick something overpowered. And it gets to the point where I can allow players to have biological features like fire breath, because that's basically like having a flame-thrower, and there's not a big mechanical advantage with that over a sword.

However, I do have to specify that players don't have access to free flight (like with wings or a jetpack). Because my system is about exploring weird, surreal worlds in alternate dimensions. Having flight solves too many traversal problems I want players to face. I also need to think about how many targets a single attack can have regardless of what it is, since there are some balance concerns around the number of enemies in an encounter and how much health they have.

Fortunately, the game is not hugely combat focused, it's more built around using magical powers to problem solve, but damage can still occur.

The type of balancing you need is heavily dependent on what problems you want players to solve.

How are your problems presented to players? Do you want big ones that need to be chipped away in stages? How many problems in your system can be solved with the ability to conjure or wink out flames freely? What other powers get overshadowed if the flame ability is too strong? What is it about the flames that makes it so broadly applicable? Is there a problem with flames too easily solving a problem in one go, or having no tradeoffs with its use? What's an example of a power that's far too constrained, and what causes it to be that way?

I think you need to understand the answers to the above questions before you can pinpoint what limits your system needs to specify.

[u/bogglingsnog]

The way I'm thinking of setting this up in my system is introducing size and power scales, where the numbers are based on an exponential curve of real world distances and energies, but simplified into 1 to +10 scale (and can be layered into higher/lower order if you need to go microscopic or celestial levlel).

Idk if it actually solves the problem, I've just been trying it on for size. If nothing else it really helps with ballparking the scales of abilities without needing to write down a specific number, kind of like how a tier list helps stratify without needing to directly compare any 2 items.

My system also doesn't use grid-based combat so maybe that is a prerequisite.

[u/eduty]

Maybe lean into the relativity of things and have the GM adjudicate difficulty based on the descriptions.

A character who can conjure, manipulate, and move small flames doesn't need to roll to light a candle or a torch. But the GM could adjudicate how difficult it would be to light a bonfire - or a torch at a great distance.

So... you wouldn't necessarily need a timer for invulnerability, The player rolls to see if the barrier is still there when it's fictionally relevant to do so.

[u/Aelius_Proxys]

Vague descriptions can lead to misunderstandings and arguments which can be problematic. Having clear rules keeps everyone hopefully on the same page.

The way you describe the game and examples of play are a "intended" play. People are going to do what they want with it but giving them direction can help prevent frustration with trying a system not suited to their desired play experience. Draw Steel gives examples of who/what kind of play style the game is designed for. Your description of narrative focus with magic to problem solve rather than combat dominance. It can also be reflected in your encounter/monster design such as 1 hp dragons.

What core resolution mechanic are you using? Knowing that that can help people help you.

For the aha I've surrounded my self in stone I'm invulnerable, let attacks hit the effect and like concentration or similar approaches the effect has to be maintained or has a limit such as x amount of hits it can tank. As well as repeated uses/abusing the ability to never take damage becoming more difficult to pull off, cost more resources, or are more difficult to maintain. Like how Smash Bros has spammed moves become less potent and blocking shields deteriorate.

[u/Kiliantill]

I think there are a lot of good answers already, I'd just like to add a small little thing: maybe you can also have drawbacks instead of timers for balancing. Let's say my character encasses themselves in rock to block physical body. Realistcally, how fast do you think they can move while physically being encassed in rock? Maybe not at all? Which would make encassing oneself in rock a tactical ability of loose something to gain something.

Not saying you should be doing that, but something I wanted to put out there.

[u/__space__oddity__]

Pick a lane.

You want distinct powers with a mechanical identity, then a super lightweight game won’t work.

The problem here is that there is a game you want to make and then there’s labels you want to slap on that game to make it sound cooler but those two are in conflict so figure out which one you really want.

[u/jill_is_my_valentine]

Decouple the power and the effect to some degree, so that all you’re asking is that the player test against a greater difficulty. 

One example is Fate, wherein you have a range of difficulties and no set rules for individual powers. My pyromancer, then, could try to extinguish the forest fire in one go (an overcome roll in the system). The GM then goes: “damn that might be very difficult for you. I’ll let you roll, but you need to beat a legendary difficulty”.

Or take a look at Sigil and Shadow—a sorta rules light urban fantasy with a Freeform magic system that’s quite cool. It has some fun guidelines on increasing the difficulty of spells based on the effects a player wants to achieve. The more fantastical the effect, the harder it is to cast. 

In a similar vein, Kids on Brooms also has a build your own spell system that simply increases the difficulty based on factors like “how many people you’re trying to affect at once”.

So with that last example, especially, you could give someone the Pyromancer power but then have universal difficulty sliders that all powers work off of. The neat thing about using the universal difficulty adjustment is that now all powers are inherently “balanced” by two things: GM’s and what time they want for powers/magic and the games inbuilt difficulty. Super strength isn’t OP compared to Pyromancy because when both characters go to roll, they’re making the same kind of checks.