Cortex Prime vs Open Legend

Compare Cortex Prime and Open Legend side by side. See differences in complexity, dice, genre, cost, and more.

	Cortex Prime	Open Legend
Genre	Universal	Universal
Play Style	Narrative, Modular, Collaborative, Toolkit, Roleplay-Heavy, Character-Driven, Tag-Based	Toolkit, Classless, Hackable, Heroic, Modular, Character Building, Tactical, Crunchy
Core Mechanic	Assemble a dice pool from trait sets (attributes, skills, relationships, etc.) rated d4–d12. Roll the pool, keep the two highest for your total vs. opposition, then choose an Effect Die from the remainder to determine magnitude. Plot Points let players add dice, activate abilities, or alter the narrative. Every mechanical element is a swappable mod.	Roll a d20 plus one or more attribute dice (d4 through d12 based on attribute score, scaling to multiple dice at higher scores) against a Challenge Rating. All dice explode on their maximum face and can keep exploding without limit. Characters have eighteen attributes split across Physical, Mental, Social, and Extraordinary categories; extraordinary attributes channel banes (negative effects) and boons (positive effects) instead of tracking a spell list. Advantage or disadvantage adds extra dice and drops the lowest or highest before summing.
Dice	d4–d12 dice pool	d20 + d4–d12
Complexity	Medium	Medium
Accessibility	High	Very High
Runnability	Very High	Medium
License	Cortex Creator License	Open Legend Community License (SRD)
Cost	$$	Free / $$
Publisher	Dire Wolf Digital	Seventh Sphere Publishing
Year	2020	2018
Best For	GMs who want to build a custom system from modular parts: homebrew designers, genre-mixers, and groups tired of forcing their stories into a pre-built framework.	Groups who want a single classless engine to handle fantasy, science fiction, modern, or horror campaigns through eighteen attributes spanning physical, mental, social, and extraordinary domains, with magic and special effects folded into the same dice mechanic as combat.
Highlights	Highly modular: 18+ mods for core rules alone, clear writing with worked examples, Plot Point economy creates dynamic give-and-take, powered well-known licensed games (Marvel Heroic, Firefly, Leverage)	All dice explode on maximum rolls with no cap, producing occasional dramatic result spikes through the same mechanic that handles ordinary rolls. Magic is folded into the attribute system through banes and boons, so extraordinary attributes like Energy or Entropy roll for fixed effects rather than tracking a spell list. Hits that exceed a defense by ten or more automatically apply a free bane on top of damage, so big roll-overs translate into status effects like knockdown or stunned rather than wasted overflow.
Considerations	Not playable out of the box: requires significant GM assembly, steep learning curve to understand which mods fit your game, every roll involves choosing which dice to keep plus an Effect Die which slows resolution	First-level character creation spends 40 attribute points across 18 attributes plus 6 feat points across a tiered feat list, producing heavy upfront decision load before play begins. Weapons have no damage dice (damage equals your action roll minus the target's defense), so weapon variety within a category is largely cosmetic, and the book itself notes that a longsword mechanically dominates a shortsword. Hit points come from Fortitude, Presence, and Will (HP = 2·(F+P+W) + 10) rather than from level, so a character who dumps all three stays near 10 HP regardless of how much XP they earn.