I get the impression that the Cortex RPG system has evolved in several directions since the release of the Serenity RPG.

Not including genre-specific changes like whatever rules for the supernatural must be in Supernatural, what rules or mechanics have been changed/improved that are applicable to any game and setting using Cortex?


3 Answers 3


Good timing: we just walked through rule changes.

I believe one of the big changes deals with experience points. The original Serenity rules had a (IMHO) stupid transition point between Plot Points and Advancement Points (if you held onto more than six plot points, you converted the extra to Advancement Points). The new rules scrapped it and just has two different types of points. This was changed quite quickly in the rules.

Leveling up is a lot simpler and smoother -- you just convert experience points to Attribute Points, Trait Points, or Skill Points, and spend them. The original rules encouraged you to specialize quickly, because it was a pain to get really good at something through Experience Points alone.

There's an alternative way of creating a character straight from experience points.

Assets and Complications are rated similar to traits ("d2" in Allure, "d6" in Cowardice). Most assets say that "add your asset to a roll" or "subtract your complication to a roll", which I think can be interpreted as step changes or add additional dice that impact the roll. Our group adds/subtracts dice, if only because it is totally awesome when someone makes a roll and gets -4 on the roll.

Sprinting triples movement, cannot dodge, and doesn't require an Athletics roll.

Autofire is changed pretty significantly. I can look up the details if you are interested, but we never really used the old autofire rules.

Shooting into crowds in the new rules is slightly different: botches are if you roll 1's or 2's instead of all 1's.


This is a bit hard of a question to answer, since you included Leverage in the tags, which includes Cortex Plus as a result. Both Smallville and Leverage use Cortex Plus as a base, which isn't really the same system, but more of a design language that influences the design of a specific system.

The previous Cortex systems are something like Savage Worlds, and honestly they were mechanically so boring that I couldn't tell you the differences between Serenity or Supernatural. I can, however tell you some of the differences between original Cortex and Smallville and Leverage.

Original Cortex follows a standard attribute + skill generic system. Smallville instead uses a combination of relationships and drives, so your chance of success in any action depends on how important the person involved is, and how important the key issue is to you. Smallville also has multiple types of stress, including fatigue, injury, and anger. It's a lot more interesting damage wise than previous systems. Smallville also makes heavy use of plot points to influence actions, and also to use super abilities. Plot points are acquired when inconvenient or bad but interesting things happen to you, which rather matches why Clark always runs into trouble with Kryptonite before getting out.

Leverage goes a bit back, having a combination of attributes + roles. So you have the 6 attributes, and 5 roles, and you use whichever attribute and role combination is appropriate. Sometimes more than one is, and you'd roll more than just 2 dice. Leverage has no damage system of any kind. You just have degrees of success or failure, and then continue until you succeed overall. If something goes wrong, you get a flashback to show how you planned for that all along, or had a plan B at least, and get to introduce that to get yourself out of a situation that you failed because of bad luck with the dice.

There's going to be a Hacking Cortex Plus supplement released at some point (this year I would assume), that would answer questions about rules changes that are applicable to both Leverage and Smallville, they may also be to some degree applicable to original Cortex, but I couldn't say until it actually gets released.

  • \$\begingroup\$ Hmmm - perhaps I should drop those tags then and focus on just Serenity and BSG for this question. \$\endgroup\$ May 16, 2011 at 2:19
  • \$\begingroup\$ Would probably help things. Supernatural is also in that same class of regular Cortex. \$\endgroup\$
    – migo
    May 16, 2011 at 2:24
  • 2
    \$\begingroup\$ -1: Savage worlds is mechanically quite different, especially since Cortex is roll & total and SW isn't. But the differences go deeper still: Cortex is GM sets a TN, dice don't open end, and stat ranges are higher while Plot Points are fewer and don't go away; SW is keep best die, seldom rolling more than 2d (1d6 for player and best of skill or stat type), dice open end, stat range is slightly lower, and the combat and advancement mechanics are drastically different. The similarity is superficial, and shared by at least a dozen other games... Chronica Feudalis comes immediately to mind... \$\endgroup\$
    – aramis
    May 16, 2011 at 4:18
  • \$\begingroup\$ It's not different enough to be interesting. Only the Cortex Plus games actually had something mechanically noteworthy. \$\endgroup\$
    – migo
    May 16, 2011 at 4:42
  • \$\begingroup\$ I concur - Leverage is almost unrecognizable as the system from Serenity. My last Serenity game was run with Savage Worlds instead, and I think was much the better for it. Leverage is a very interesting system though, and I can't wait to play it. It's very much a story-game system (which I consider to be a great thing in a "mainstream" RPG). It's also important to note that you don't always add up all the dice rolled - usually, just the best two. \$\endgroup\$
    – gomad
    May 16, 2011 at 16:07

Serenity ranks ads and disads as major or minor; later cortex games as dice.

Standard cortex remains Attribute die + Skill die for TN+.

Cortex plus changes to Ability + some other factor (Role in Leverage, Relationship in Smallville, and Solo/Buddy/Team in Marvel). Marvel allows more than two items - for example, you always add one of Solo, Buddy or Team, as appropriate for your situation, and one power per power group, and maybe a talent, but if you can narrate more powers or talents in and have the drama to activate more, you can roll extra dice. Keep the best 2 dice as your roll for TN, and the largest number of sides is the effect.

Note that the Cortex system itself predates Serenity as well; the system originates in Larry Elmore's Sovereign Stone (before the setting was converted to d20), evolves slightly with Serenity, and changes again for the later run of games. It wasn't named Cortex System until after the release of Serenity. Cortex Plus is a side branch for relationship driven settings.

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    \$\begingroup\$ Relationship is only a factor in Smallville, not Leverage. \$\endgroup\$
    – migo
    May 16, 2011 at 0:55
  • \$\begingroup\$ Yes, the system seems to be an ongoing work in progress. It is getting harder to keep up with what is changing within it, or even if an 'it' not a 'they' really exists. \$\endgroup\$ May 16, 2011 at 2:35

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