1. Static Difficulty Numbers
In the majority of systems, the difficulty of a roll depends on what the character is trying to do. The GM either consults a chart in the book or assigns a number on the fly. Landing a passenger plane in rough weather will be easier than flying a fighter jet down the Grand Canyon at combat speed. Two factors affect the probability of success: the task being attempted, and the character’s skill. An average pilot can probably manage the first task, but only a highly trained expert can pull off the second. This method is straightforward and effective.
But some systems are different. In games like Call of Cthulhu and Apocalypse World, the difficulty of a task is always the same. The only factor affecting the probability of success is the character’s skill. The immediate effect of this mechanic is to give the game a surreal feeling, because characters routinely fail easy tasks and routinely succeed difficult ones. For a lot of players, this breaks the suspension of disbelief. They have a hard time enjoying themselves in a world that seems to operate on such alien and comical laws.
More subtly, static difficulty numbers strongly discourage players from diversifying their characters. In most games, getting a few ranks in a new skill means the character can have a decent chance to succeed at easy tasks. But with static numbers, every task has the same difficulty, meaning skills with only a few ranks are useless. At the same time, being really good at a skill means the PC can achieve just about anything they like, because even the hardest tasks have the same difficulty. The end result is a party full of characters who are only good at one or two things, which they almost never fail at.
Finally, static difficulties take away an essential GM tool: making the villain more threatening. From a fiction perspective, we all know that defeating the main boss is harder than taking out mooks, but it doesn’t feel that way if everything is the same difficulty. Normally, GMs increase the difficulty of climactic rolls to represent how much the PCs must struggle to get what they want. With static difficulties, that is impossible. The big boss isn’t any harder than the campaign’s first encounter was.
The upsides offered by static difficulty numbers are minimal. They relieve the GM of the responsibility of assigning difficulties, but that becomes second nature to most GMs pretty quickly. It’s often easier to calculate the probability of success with a static difficulty, but players don’t need to know their exact chances every time. These fringe benefits are not worth all the trouble that static difficulties cause.
2. Special Abilities That Aren’t Special
Most systems have some kind of special abilities characters can take outside of standard skills and stats. They go by many names: feats, advantages, merits, etc. But no matter what they’re called, these special abilities let a character do something they couldn’t otherwise do. That’s why the abilities are special, after all.
Or at least that’s how it’s supposed to work. Sometimes, a special ability does nothing other than give a character permission to do something they could already do. For example, in Legend of the Elements, the Hunter gets an ability called Stealth, which lets the character roll to sneak past their enemies. Except, shouldn’t all characters have the ability to roll to sneak past their enemies? Moving quietly is a pretty basic concept. Not everyone is good at it, but they understand the basics.
Legend of the Elements is hardly alone in this. In the New World of Darkness, characters have to buy a special merit if they want to disarm their opponent. Without this merit, even a character with max ranks in Melee, a true master of swordcraft, has no concept of knocking the other guy’s weapon out of their hand.*
No matter which system they come from, these “special” abilities have one of two effects on the game. In the first scenario, the GM just lets everyone roll to use stealth, disarm their enemies, or whatever task is supposed to require the special ability to perform. At this point, the player who bought the special ability will be understandably upset because they wasted their points.
In the second scenario, the GM follows the letter of the rules. Only the PC who buys Stealth can try to sneak past people, and only the PC with Disarm can try to take away the enemy’s weapon. At best, the other players will chafe against this restriction. At worst, they’ll turn on the player who bought the ability as the cause of the problem. “I could sneak just fine until you bought an ability that says only you can sneak!”
Special abilities should give characters new and exciting options. If they don’t do that, there’s no reason to include them.
3. Harmless Knives
When determining how much damage weapons do, it seems natural to use size as a guide. If getting hit with a small sword hurts a little, getting hit with a big sword should hurt a lot. It all makes sense!
Unfortunately, this kind of scaling often has the effect of making it nearly impossible to injure someone with smaller weapons. Knives are the most common victim, but slings and staffs suffer as well. In systems like Burning Wheel and Legend of the Five Rings, even master knife-fighters have difficulty inflicting a hit of any significance.
Mechanical Explanation of Knives
Attacks in Burning Wheel can inflict three levels of damage: Incidental, Marked, and Superb. Someone with 4 Power who’s wielding a knife inflicts a strength 7 Superb hit. That’s a medium wound for most characters, and it’s the most a knife wielder can ever get, and they need two successes over the obstacle to get it. Most of the time, they’ll have to make do with a Marked hit at best, which is barely a scratch.
In Legend of the Five rings, knives do 1K1 damage. That means 1d10 is all you get. A character’s strength, usually 2-4 is added in unkept dice, so you’re looking at between 3K1 and 5K1 for damage, but you still only get to keep the highest die. PCs can make their attack roll harder in order to roll more dice on damage, but they only get to keep more if they get over 10 dice, which is practically impossible. So no matter how good and/or strong the knife fighter is, they’re only keeping one damage die. That’ll barely slow a bandit down!
At best, characters need to hit their opponent many times over in order to cause any harm. At worse, even that is ineffective. It gives the impression that the character is wielding one of those trick knives that slides back into the handle. To say this breaks suspension of disbelief is an understatement. Most players know that knives in the real world are dangerous, that they can easily maim or kill. A game that treats them as toys will destroy immersion fast.
But a loss of immersion is nothing compared to what happens if a player decides their character will be a knife fighter. The player imagines their character darting in and perforating the enemy’s kidney, but in reality they inflict little more than a paper cut. That’s enough to make even a patient player walk away from the table.
Beyond the mechanical limitations, this kind of mechanic negatively impacts a game’s setting as well. A gang of dangerous cut throats and their switchblades will suddenly seem quaint and nonthreatening, as will the monastery of kung fu monks armed with quarterstaves. It’s even possible that players without a foundational knowledge of weapons will leave the table thinking that such weapons are harmless. Then those players will write fantasy novels where everyone needs a sword the size of a car to do any damage.
4. Useless Immunities
Not all special abilities let a character do something new. Instead, some of them grant immunity to one or more kinds of harm. This might be something as simple as immunity to poison or as abstract as protection against harmful insults. So long as these threats are actually present in the game, then immunity is a valid ability. But too often, systems give players the option to protect themselves from something that was never a danger in the first place.
The best example of this is the Kaiu Blade from Legend of the Five Rings (L5R). This is a special sword PCs can buy at character creation. It does more damage than a standard katana, but more importantly for our purposes, it is unbreakable. Based on that description, you might think having your sword broken is a serious problem in L5R, but it isn’t. If there are any mechanics for breaking swords, a decade and a half of playing hasn’t been enough for me to find them. Even if they’re buried somewhere in an obscure supplement book, it’s clearly not a common problem.
The Kaiu Blade is just one way this mechanic can manifest. It also crops up in abilities that grant immunity from a single type of poison or a D&D feat that allows characters to cast spells without their material components. Chances are very low that someone will target a PC with the specific poison the PC is immune to, and spell components are practically ignored by D&D’s rules anyway.
These useless immunities leave the GM in an awkward position, similar to what happens with “special” abilities. If the GM runs the game normally, the player who purchased the immunity will feel like their points were wasted, because they were. Alternatively, if the GM goes out of their way to make the immunity useful, it will punish the other players.
Consider L5R again. There’s a reason the game isn’t full of monsters that break swords. Katanas are hard to replace, and without them a samurai isn’t much use. It wouldn’t be very fun for the group if they were suddenly attacked by the Oni of Broken Swords, just so that the points one player spent on a Kaiu Blade wouldn’t be wasted.
5. Penalties as Difficulty
Most systems make a task easier or harder by increasing or decreasing how much a PC has to roll in order to succeed. A few use a static difficulty, as we talked about earlier. But there’s a third method that’s somewhere in the middle: systems that change the difficulty of a task by giving the PC penalties.
Technically, Call of Cthulhu works this way, but the penalties are so vestigial that most GMs forget to use them. For a system where they are more baked in, we must look to the Chronicles of Darkness.* In that system, characters roll a number of dice equal to their attribute plus their skill. Any die that comes up eight or higher is a success, and PCs only need one success to pass a test. At first it seems impossible to fail, but the GM is supposed to subtract dice from the PC’s pool based on how difficult something is.
Mathematically, this system isn’t any different from changing the number of successes required for a roll, but from the players’ perspective it makes all the difference. When players are told they must roll against a high difficulty, they accept it unless the number is unreasonable. But when players are given penalties to their rolls, even when the penalty is reasonable, they’ll contest every lost die.
Players aren’t doing this to be difficult, they’re doing because getting penalized doesn’t feel good. In the moment, it feels like the GM is picking on them. Broadly speaking, players have been trained to understand that a higher difficulty means the task is harder while penalties to their rolls mean there’s something wrong with their characters. So when their rolls are penalized, they don’t see it as an attempt to do something difficult but as a sign that their characters have become incompetent.
Penalties are fine so long as they come from a problem connected to the character. Most players will accept that their character’s broken leg gives them a penalty to their attack rolls. But they’ll have more of a problem with the idea that they should be penalized because the target is far away.
Finding one of these mechanics in your favorite system doesn’t mean you have to throw it out. Many systems are good despite such flaws, but they are unquestionably flaws. If you’re looking to design your own system, leave them out. Your playtesters will thank you.
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