Different Dice Mechanics

So, when playing AW, one thing my players didn't like is the static difficulty. They didn't like that they were always trying to roll the same numbers, and that difficult situations weren't more difficult. So, I'm working on a hack at the  moment, and it's a horror game, and I figured a sliding scale of difficulty would make the players feel less like badasses and more vulnerable. As well as that, after playing Numenera I like the idea of having a resource you can spend to alter difficulty. But, I also like the AW idea of granular success; of having a fail, a success but, and a success.

So, after putting all my ideas together, I got something like this, and I just want your opinion of it.

Roll+Stat to use a move. The difficulty of the task determines the die.

Near Impossible    – d4
Very Difficult       – d6
Difficult              – d8
Challenging            – d10
Average              – d12
Easy               – d20


7 or less is a fail
8-10 is a success, but
11+ is a clean success.

But the characters have a resource called Energy which also acts as their health. They can spend energy to reduce difficulty.

So yeah, can anyone offer some feedback in this area.

One thing I have a little bit of a problem with is at high difficulties, the probabilities are higher. So say if, for example you have a 4 in a stat, then succeeding a near impossible task is 1/4. Sure, it's still easier as difficulties decrease, but that's still a high chance of success.

Interesting concept. I'd suggest looking at the 'spread' of using 2 dice as opposed to 1. The issue with using 1 dice is that it's *very* prone to wild variance, where-as a 2 dice roll will concentrate the rolls around the middle. For most *World games, the spread of 2d6 means that, more often than not, you're falling into the 7-9 range. This allows the players a sense of progression while providing new challenges to keep the story going ("you succeed BUT..."). I'd have to check my math, in the system you laid out, you are more likely to have a complete success on a Challenging task with 1d10+Stat  than you are with 2d6+stat.

The *World games tend to handle difficulty by adding rolls. The more a player rolls, the more likely they are to fail or at least cause complications. Each roll needed to overcome the obstacle increases the difficulty of that obstacle in an organic fashion. For a horror game, I would personally force players to overcome terror, insanity, nausea or exhaustion whenever they try something hard.

In your hack, consider limiting stat bonuses. A +3 or +4 is enormous in the 6-/7-9/10+ system. You could have a completely different stat distribution; say -2, -1, 0, 1, 1. That would greatly change the dynamic and difficulty of the game.

Finally, don't underestimate the power of re-framing. Think about the names of your Moves, and the names of your stats. Apocalypse world has Cool, Hot, Sharp, Hard and Weird; those don't fit in a horror game at all. Horror protagonists are none of those (well, except weird, maybe). My own Space Opera has Mettle, Physique, Influence, Tech and Ingenuity as stats instead, because that distribution works with many of the tropes of sci-fi shows like Star Trek or Firefly. For a horror game, the stats should reflect the desperation of the characters. It's all in the language; saying "Roll plus your Hot" says something about your setting. "Roll plus your Sanity" says something completely different.

For a horror hack? Personally I'd go for:
- Flesh (Strength, Speed)
- Blood (Toughness, Endurance)
- Mind (Knowledge, Skill)
- Heart (Sanity, Courage)
- Soul (Magic, Supernatural)

Thanks for the reply, it's very helpful. I especially like those stat ideas and I may well steal them!

As far as your maths goes, I think you've got it wrong. From what I worked out, you're significantly more likely to fully succeed with 2d6, overwhelmingly so at higher stat bonuses.
At +3, a roll of 10+ has a probability of 58.34% with 2d6, whereas an 11+ on a d10 at +3 has a 30% chance. Even at just +1, it's 27.78% on 2d6 or 10% with d10.

I really feel like the ability to alter the difficulty of a roll adds something to the game, an element of resource management and planning. Limiting stat bonuses definitely makes the game harder, but it's not dynamic and changeable by the players. It also makes the near impossible d4 actually impossible, making its existence pointless.

So, I guess the problem is that there's too much uncertainty with changing the dice. The results become more random as they get easier. But, at the same time the probability of rolling higher does increase. And even at a hypothetical +4 in a stat, 1/4 chance to succeed a near impossible task, is still a "success, but".

Sorry if this got a little incoherent toward the end; just trying to work things out.

I tend to calculate spread based on the assumption of +0 to the roll, because that's what's expected of a 'normal' person. +1s and higher are supposed to represent exceptional people, people who have a greater chance of success. If you ratchet down all chances of success, using nigh superhuman +3 as your median, it both greatly devalues having a +3 (because it's expected, not exceptional) and it makes things exceptionally less enjoyable for everyone else (actively discouraging anyone who has a +0 from attempting it at all).

So you reckon I should bring it down to the same ranges as AW? 6-/7-9/10+?
Still, if I keep +0 as my median to calculate things, that still means that a near impossible, d4, cannot be realistically attempted. And, just stands a place holder for something to be easier than. Hell, even the very difficult d6 can't be attempted without at least +1... Hmm... I may have to think harder about this...

I think Archangel3's initial point is a good one and has been overlooked.  Using more dice concentrates your probability curve towards the center.  If you're only rolling a single die, you are equally likely to get any particular result.  As soon as you are rolling two dice, you start seeing the bell curve, where you are more likely to end up in the middle than at the extremes.

For instance, keeping the same 6-, 7-9, 10+ breakdown, say you are rolling 2D4 with a target number of 6.  There are only 3 possible outcomes (out of 16 total) that meet or exceed the minimum target number for partial success (minimum 7), so your chance of success is only 18.75%.  Your highest possible outcome is an 8, which is only a partial success.  If you are rolling 2D6, you will succeed 58.3% of the time, and have a full success (10+) 16% of the time.  If you go up to 2D8, you will succeed 76.5% of the time.  At 2D10 you will succeed 85% of the time, and so on.  Your partial success band changes size as well, though as your dice size goes up your changes of getting a full success actually become more likely than getting a partial success (which may be what you want).

Adding in a modifier on top of this obviously changes things.  I think the thing you need to figure out is: what likelihood do I want for a "virtually impossible" task versus a "very easy" one.

But maybe a more important question is to take that abstraction a step further and ask, "do I really want to make the players roll for something that is "very easy?"  This addresses the wider philosophical question of what it is that random chance is adding to your game and how it will be incorporated.

Apocalypse World is very "fiction focused," as opposed to being an accurate simulation of reality (or unreality).  When people talk about the "odds of success," there is often an implicit Simulationism (I know, I know, but for lack of a better word...) at play.  But Apocalypse World doesn't really have "difficulty modifiers," so that kind of aspect is almost completely absent from the game.  If disarming a bomb before it explodes is acting under fire (for instance), then what is disarming a bomb with no tools in the pouring rain while being shot at?  The answer is probably still acting under fire.  The fiction itself (the lack of tools, the presence of the rain, the enemy fire) doesn't dictate the difficulty of a single roll, it dictates when that roll takes place.  If there's enemy fire, you might have to act under fire to get to the bomb in the first place.  Once you're there, disarming it with no tools might be another roll.  The difficulty comes not from modifiers to any single roll, but from the fact that you might have to make more than one (essentially decreasing the chances that you'll succeed at all of the rolls).

This is an important, doctrinal, paradigmatic difference in gameplay.  Before you go too much farther, you should decide how you want to use the dice in your game, what you want an individual roll to mean, and whether that die roll is there to simulate difficulty or to introduce dramatic tension.

AnyDice can help you visualize your dice prob curves.  Type in "output 2d6+3" (for example) and click "calculate".  It will draw the curve and calc the probs for you.

Munin, that's really helpful! I guess I need to take a look at the purpose of the dice rolls, look at them as furthering the plot and dramatic tension, rather than just a numerical obstacle to get past.

As If, I love that site. I've been playing with probability curves all day. Someone on another site was suggesting d4 pools.