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Admittedly a very specific/niche question but I was curious as to what the perceived benefits are to the critical hit system that Corvus Belli's Infinity wargame uses versus the more common crit on a 1 or 20 depending on whether you roll under or over to succeed. For reference...

https://infinitythewiki.com/Rolls#Criticals

Basically you have an attack value that you're attempting to roll under (after modifications) to succeed. If you get the exact number for the threshold on your roll then you score a critical hit. I'm curious what benefits this has over the more traditional d20 method.

I can't think of many mechanical ones off the top of my head but admittedly I don't have the knowledge base to do a real statiscal comparison. How much of an effect does increasing the range of crits (with thresholds over 20) make in this case? Mechanically, that's the only one that pops out for me personally. I suppose simple variety in the number needed for a crit depending on the statline instead of a one sized fits all 1 or 20 is also a potential small benefit counterbalanced by the added complexity of having to know the individual crit value (which likely you already need to have in memory simply to know if the test succeeds). From a branding perspective, I suppose having a unique mechanic (that no one else uses?) is a benefit. That's pretty much all I came up with and was curious if anyone else has rubbed a couple more brain cells together than me on the topic.

Statistically, hitting any one give number between 1 and 20 with a D20 is equally likely as hitting specifically 20, so there's no statistical difference between the two.

The difference occurs when you can exceed 20 with modifiers: in this case you get a crit when rolling a 20 or above and on top of that add your excess success to the result of the roll. So a dude that got to 30 with addons would roll for crit and get one with any roll 10 and above.

So it seems like the main difference is that especially lopsided interactions have a much higher chance to produce a critical - once you go over 20, your chance of a critical increases in a linear way until it reaches 100% at 40.

To recap:

As long as you stay in the corridor of 1-20 after modifiers, the system is functionally identical to 'Crit on natural 20' - if you go over 20 your chance of a critical hit increases by increments of 5% for each point above 20.

Mathematically there is no difference. Which number on the D20 you select is irrelevant since all are equally likely to appear. From a design point of view the 1 and 20 system matches what we intuitively think of as best and worst outcomes, and there is some value in that. The only time you'd have a functional difference is if you have other rules which trigger on certain die results. For example, if you have a rule where a 1-10 on the D20 does splash damage it's very relevant if 8 is your crit number or 20 is your crit number. But if the crit rules are considered in isolation then that's not an issue.

As for results of 21+ the traditional interpretation of the 1 and 20 system is that they refer to a natural 1 and 20. It doesn't matter what modifiers you have or how high you can boost that final result, if you don't have a 20 showing on the physical die you rolled you don't have a crit. If you're using that version then there's no concern about getting extra crits from a result of 21+.

Tsagualsa wrote:

To recap:

As long as you stay in the corridor of 1-20 after modifiers, the system is functionally identical to 'Crit on natural 20' - if you go over 20 your chance of a critical hit increases by increments of 5% for each point above 20.

Yeah, that was the main one that I thought of as well. Any thoughts on the higher is better if still under opposed roll mechanic?



Automatically Appended Next Post:

Aecus Decimus wrote:
As for results of 21+ the traditional interpretation of the 1 and 20 system is that they refer to a natural 1 and 20. It doesn't matter what modifiers you have or how high you can boost that final result, if you don't have a 20 showing on the physical die you rolled you don't have a crit. If you're using that version then there's no concern about getting extra crits from a result of 21+.

Thanks for pointing that out as I didn't mention that the modifiers in Infinity seem to go on the target number and not the roll. It doesn't affect the game mechanically but it's a good point to make that you're always referring to the naked dice result and not modifying it.

Does anyone know if the Infinity RPG use a similar mechanic?

 warboss wrote:

Yeah, that was the main one that I thought of as well. Any thoughts on the higher is better if still under opposed roll mechanic?

I think it works quite well specifically as an opposed roll mechanic. It makes it so an increased skill value both results in a higher overall success rate AND more opportunities to roll higher than the opponent.

Often time things like this are less about the roll itself and more about the stats behind them as well. One thing I often see designers fail to appreciate is how much it matters to players that having a bigger stat makes you better and things like cover that lower your number are seen as a penalty. There are probably other ways of accomplishing the same probability bands, but they might not get the right feel.

An interesting thought exercise on this is that the game once upon a time had you roll damage against an opposing armor value. This changed when players reacted better to rolling armor against an opposing damage value despite the actual math not changing. I actually just did something similar with Alpha Strike after noticing that resolving attacks feels more complicated than it actually is and can be pretty easily reworked into the RAT/DEF system of Warmachine without actually changing the game in any way.

That is true. You can have the exact same mechanics at play in a two step resolution but have two different feels if you have one player roll both or split them between the players. Does any other game use a similar mechanic to Infinity where you need to roll the stat for a crit? I can only recall roll under/roll over and 1/20 crit systems personally but I haven't exactly been spreading my gaming wings over the past decade.

How does the mechanic work in Alpha Strike? I only played it twice and it seemed too simplistic for my tastes (which is odd since I find CBT too complex as well, lol). My problem specifically though was lumping all weapons together into a range band...

A 12 on 2d6 is required for a critical hit in alpha strike, regardless of the target’s armor/structure. It’s like you lined up the perfect shot to exploit a weak spot.

Any hit that causes at least one point of structural damage is also a critical hit.

I'm not aware of any game that resolves like Infinity. It remains pretty unique in my experience.

Warmachine does criticals on any doubles for 2D6, but you still have to hit, so the chances improve with higher success rates. It just doesn't matter all that much because Crit effects are relatively rare.

 LunarSol wrote:
I'm not aware of any game that resolves like Infinity. It remains pretty unique in my experience.

Same here which I find odd. It seems like it might work really well in an RPG where the model counts are typically very low and spread out amongst multiple (4+) people typically.

 warboss wrote:

Tsagualsa wrote:

To recap:

As long as you stay in the corridor of 1-20 after modifiers, the system is functionally identical to 'Crit on natural 20' - if you go over 20 your chance of a critical hit increases by increments of 5% for each point above 20.

Yeah, that was the main one that I thought of as well. Any thoughts on the higher is better if still under opposed roll mechanic?



Automatically Appended Next Post:

Aecus Decimus wrote:
As for results of 21+ the traditional interpretation of the 1 and 20 system is that they refer to a natural 1 and 20. It doesn't matter what modifiers you have or how high you can boost that final result, if you don't have a 20 showing on the physical die you rolled you don't have a crit. If you're using that version then there's no concern about getting extra crits from a result of 21+.

Thanks for pointing that out as I didn't mention that the modifiers in Infinity seem to go on the target number and not the roll. It doesn't affect the game mechanically but it's a good point to make that you're always referring to the naked dice result and not modifying it.

Does anyone know if the Infinity RPG use a similar mechanic?

You could make a similar system by having a roll of 20 always crit, and lower all the stats by 1. Any stat 20+ inclusive adds +1 to roll. This is functionally not different, and it allows you to put your cool 'symbol' on special dice on the 20 be the 'crit', to match D&D.

However, there is an arguable good 'feeling' of rolling the exact number you need to hit. You are already focusing on that number, because that is the breakpoint to actually hitting - Hitting that number exactly for crits makes it feel special, even if it makes it harder to recognize the 'crit' immediately after rolling (especially for the opponent, who is usually focused on THEIR number instead). It also psychologically makes you excited about all sorts of different numbers, as opposed to always praying for a single number (1 or 20).

IMHO I am biased to rolling 20s for crits, because that way my cool D&D dice have the symbol on the crit, but I waffle on if it's actually better because of the different psychological impact of the different crit numbers. Which positive is actually better? I don't think it's easy to know, without A/B testing, and even then, I would suspect different people would prefer different crit confirmations.

Technically the actual practical effect of having the crits be on the specific roll versus having a crit on a 1 or 20 is that you can do higher-crit-wins on the roll-off. Infinity applies modifiers only to the target number, so if you were doing a d20-system die+modifiers v. target number thing instead you could create a similar effect by saying "if I roll a 20 and you roll a 20 then whoever's modifiers are higher win!", the Infinity implementation is just that applied to how it handles numbers.

In practice it doesn't really matter for a game where you're rolling a small number of d20s; in something like D&D you're rolling a single die against a static DC to make an attack, versus Infinity where you're rolling 3-5 dice on many attacks that are usually opposed by 1-2 dice from the other side, so you see a lot more crits during play.