Tell Me About Cortex Prime

[aramis erak]

Yes, IIRC it first appeared in Sovereign Stone (a RPG I’ve never read based on some Weis fantasy books I’ve never read either) but then MWP got the BSG license and decided to use those rules there.

The other Weis property associated with Cortex is of course Dragon Brigade, but I don’t think I’ve ever seen anything other than the QuickStart there.

Cortex Classic starts with Sovereign Stone. Jamie Chambers wrote the system. Based upon Larry Elmore's Sovereign Stone novels.
It gets the name Cortex from Serenity RPG. Also Jamie Chambers.
Then several other Cortex Classic games (including BSG)...

Cortex Classic, all of which I've read are Stat die + Skill Die + optional_Plot_Point_Spend_Die, summed, vs a TN or an opposed roll. It was all rated in dice codes... and that's about where the similarities end.

Then, with Smallville, Cam and Josh got experimental... and Cortex Plus was born.

It got its big breaks with Marvel Heroic and Firefly... two very different takes on the formula of Cortex Plus. Leverage goes even simpler - the simplest of the Cortex Plus games 6 roles, 6 attributes, distinctions, and assets. Then they added a new role in a supplement. Still, simple, elegant, perfectly suited to the setting.

 

[Parmandur]

That's by design. The exact odds of any given roll are a little hard to suss out, and for the type of genres Cortex is trying to emulate, that tends to be for the best. There's several axes to consider, and you're often pushed to make choices that are suboptimal for any given roll because they net you other things (either Plot Points or different narrative outcomes), so it works really well for that.

Oh, I'm into it, but I'm a dice rolling sicko. I see it as a hard sell and likely hard for the average player, even numerate players, to get a good grasp on.

 

[chuckdee]

Cortex Classic, all of which I've read are Stat die + Skill Die + optional_Plot_Point_Spend_Die, summed, vs a TN or an opposed roll. It was all rated in dice codes... and that's about where the similarities end.

Thanks for delving into that. I thiught the sovereign stone was a different system (so different that they named it differently) but I couldn't remember

 

[Kannik]

And this reminds me inevitably about what I think doesn't work about CP, which is the dice balance issue and feel. You basically try and gather an appropriate handful of dice (say Attribute, Skill, Distinction, Ability) and get a decent result. Differences in levels of those stats don't feel very meaningful - you're rolling d6, d8, d8, d6, for example, which doesn't feel very different from d6, d8, d8, d10 for another combination - and it's hard to tell that you're actually better at one thing than another. And the number of dice matters - if you're only rolling Attribute + Distinction that is very different from rolling 4 or 5 stats, it's much more swingy. But if you have a lot of dice, they can all feel pretty samey. Does that make sense to anyone else?

Partially makes sense. The only aspect (pun semi-intended) I'm not keen on w.r.t. Cortex Prime is that with all the different die types and number of dice it's hard to get a base grasp on probabilities of success. Then you throw in that the difficulties are also a roll (though there is the option for static difficulties, and I'm working on a hybrid) and it gets even more nebulous beyond "bigger dice and more dice = better."

But how the die opens up pure elegance on the GM side for things like bosses, mobs, crisis pools, challenges, and the doom pool mod, and it that annoyance becomes something worth living with. That said, it is a good reminder for the GM to telegraph what the relative difficulty of something might be so that the players/characters are informed and can make appropriate choices (which could be to risk it!).

While it's tempting to choose your best stats (Glory d10, Lois Hates Me d10) you usually don't because they're not appropriate and they don't feel right. So you decide you're actually really motivated by Justice d8 and Clark is A Whiny @$$Hole d8 on this roll, which feels like a meaningful choice (even if it is less so on the dice expectation, as it were).

Aye! The number of times I've had things be fully in the moment and characters taking action totally fitting with and logical for their character, only for the player to realize a moment later that it's not their strongest option... ah, it's great. Very fully invested in the character and the unfolding moment.

I thought this was a real problem in Leverage, where the baseline is Attribute + Role. It's obvious what you're supposed to roll when Eliot beats people up, but for a game or setting where Eliot is supposed to be and feel amazingly awesome at beating people up, he didn't feel that way at all unless he used his Distinctions (which, of course, weren't like Distinctions in Cortex Prime - they were basically special abilities, a bit like Stunts in Fate) to narratively rule that he beats people up awesomely. The Distinctions were the only way he felt, in the game mechanics, significantly better at Hitting than Hardison did, which absolutely should not be the case.

Cortex Prime has you including a Distinction in every test, which really brings character elements to the fore and therefore the opportunity in every test for it to be something meaningful and/or cool. (I have a longish writeup here about how the same "everyday" test can end up influencing things in three very different ways depending on which Distinction the player chooses.)

Then, to further distinguish between the same Approach + Role (for example) there's also Specializations and especially SFX. The former will help on every test if the player is a bruiser, so making them better than their teammate who isn't, and SFX just puts a bow on it when they do something totally out of the ordinary.

So I guess what I'm saying is that it may be worth considering another RPG system than Cortex for game settings where greater talent, skill, competence, and power levels matter and are part of the gameplay loop, unless you're slotting something like Leverage Distinctions in there to bypass the system.

While Leverage might not have had it fully baked yet (being from the early days of Cortex Plus), I think now between Distinctions and SFX (and Signature Assets and Specializations and a few others), within Cortex Prime there are enough to distinguish skill, competence, and expertise between different characters within the same group. (Another example in that favour is that it handled Marvel with the wide array of different abilities/powers/capabilities that comes from a bunch of superheroes).

But for a setting where motivations, relationships, and narrative and character choices really matter, then Cortex shines almost uniquely as a perfect jewel.

And absolutely here too! Which, nicely, also didn't go anywhere with the support for expertise and etc, so you can still have that rich narrative underpinning even while you are super skill monkey special operatives.

 

[aramis erak]

Thanks for delving into that. I thiught the sovereign stone was a different system (so different that they named it differently) but I couldn't remember

It's exactly the same character mechanics as Serenity...

 

[jian]

Partially makes sense. The only aspect (pun semi-intended) I'm not keen on w.r.t. Cortex Prime is that with all the different die types and number of dice it's hard to get a base grasp on probabilities of success. Then you throw in that the difficulties are also a roll (though there is the option for static difficulties, and I'm working on a hybrid) and it gets even more nebulous beyond "bigger dice and more dice = better."

But how the die opens up pure elegance on the GM side for things like bosses, mobs, crisis pools, challenges, and the doom pool mod, and it that annoyance becomes something worth living with. That said, it is a good reminder for the GM to telegraph what the relative difficulty of something might be so that the players/characters are informed and can make appropriate choices (which could be to risk it!).



Aye! The number of times I've had things be fully in the moment and characters taking action totally fitting with and logical for their character, only for the player to realize a moment later that it's not their strongest option... ah, it's great. Very fully invested in the character and the unfolding moment.


Cortex Prime has you including a Distinction in every test, which really brings character elements to the fore and therefore the opportunity in every test for it to be something meaningful and/or cool. (I have a longish writeup here about how the same "everyday" test can end up influencing things in three very different ways depending on which Distinction the player chooses.)

Then, to further distinguish between the same Approach + Role (for example) there's also Specializations and especially SFX. The former will help on every test if the player is a bruiser, so making them better than their teammate who isn't, and SFX just puts a bow on it when they do something totally out of the ordinary.


While Leverage might not have had it fully baked yet (being from the early days of Cortex Plus), I think now between Distinctions and SFX (and Signature Assets and Specializations and a few others), within Cortex Prime there are enough to distinguish skill, competence, and expertise between different characters within the same group. (Another example in that favour is that it handled Marvel with the wide array of different abilities/powers/capabilities that comes from a bunch of superheroes).


And absolutely here too! Which, nicely, also didn't go anywhere with the support for expertise and etc, so you can still have that rich narrative underpinning even while you are super skill monkey special operatives.

I do think static difficulties (and maybe static bonuses) are the way to go a lot of the time in some versions of Cortex. It’s just more predictable if you know the set difficulties (5 is easy, 7 is average, 9 is hard, 11 is very hard, 13 is basically impossible) and easier to assess in your head as a player how likely you are to succeed and thus how good you are.

I also have rather fallen out of love with the Doom/Trouble Pool as written over time and many sessions. I love what it’s supposed to do - gradual escalation through the session, give players PPs - and it reminds me of Doom cards in Marvel Saga, which worked great. But I don’t think the pool dice should be the baseline difficulty for all checks, I think they should be a pool for the GM to add or spend to mix things up.

Or dispense with the Doom Pool entirely and just use static difficulties (as above) or NPC stats as well as giving PCs a d6 Complication or similar when they roll a 1, much as ToX does for those.

 

[Kannik]

I do think static difficulties (and maybe static bonuses) are the way to go a lot of the time in some versions of Cortex. It’s just more predictable if you know the set difficulties (5 is easy, 7 is average, 9 is hard, 11 is very hard, 13 is basically impossible) and easier to assess in your head as a player how likely you are to succeed and thus how good you are.

I'd be leery of trying to switch to some static bonuses, that gets the math really wonky (the Roll Many Keep 2 + die type for effect would be very disrupted by adding a non-die value). So I'd keep it only to the fixed difficulty number (or the hybrid of fixed for the base difficulty + dice for assets). The only thing is that without the base difficulty dice there's no chance for Opportunities (where the dice roll a 1) for the players to engage with, and so I need to review what Opportunities are possible and ensure they're covered in another way.

I also have rather fallen out of love with the Doom/Trouble Pool as written over time and many sessions. I love what it’s supposed to do - gradual escalation through the session, give players PPs - and it reminds me of Doom cards in Marvel Saga, which worked great. But I don’t think the pool dice should be the baseline difficulty for all checks, I think they should be a pool for the GM to add or spend to mix things up.

While I know it's very popular among many Cortex players, I've never played or run with the Doom Pool mod. Partially because the games I've run I don't think are right for it, but also I don't think I have a good grasp on how to best use it (not in the straightforward mechanics way but how to relate to it and relate it to the players to enhance the tension and mood of the moment). I really need to see it in action someday so I can grok it.

Though I also don't feel like I've necessarily lost a lot by not using it, again at least for the games we've played. I can still use Challenges (which are awesome) and other things with pools, and the standard difficulties still work great with everything else.

 

[pemerton]

And this reminds me inevitably about what I think doesn't work about CP, which is the dice balance issue and feel. You basically try and gather an appropriate handful of dice (say Attribute, Skill, Distinction, Ability) and get a decent result. Differences in levels of those stats don't feel very meaningful - you're rolling d6, d8, d8, d6, for example, which doesn't feel very different from d6, d8, d8, d10 for another combination - and it's hard to tell that you're actually better at one thing than another.

This doesn't fit with my experience. When I've played Marvel Heroic RP, and my Heroic Fantasy hack of it, the difference between dice sizes in the pool has been pretty noticeable.

Affiliation is as boring as hell - the situation decides whether you're alone or whether you've got your team with you, not you.

I agree that Affiliation is not the most exciting thing in itself, but (i) it is something the GM can lean into by using Doom Pool dice to separate or rejoin PCs, and (ii) it is not always outside of the players' control: they can make decisions to have their PCs separate, or join up with one another.

 

[pemerton]

I have no real play experience, but just having read a bit and talked to other people, I have always felt that the pooling elmechabic, while cool, is less intuitive than a more flat core mechanic system like d100 roll under, 2d12 roll high, or d20 roll over for quick estimation of what a character can do.

Cam Banks has said that the difficulty of estimating probabilities is a deliberate feature: it encourages building your pool of dice based on what you think is going on with your action in the scene, rather than trying to calculate probable outcomes.

 

[Parmandur]

Cam Banks has said that the difficulty of estimating probabilities is a deliberate feature: it encourages building your pool of dice based on what you think is going on with your action in the scene, rather than trying to calculate probable outcomes.

OK, fair enough. Just seems like a factor thst limits uptake for the game.