Call of Cthulhu vs Eclipse Phase

Compare Call of Cthulhu and Eclipse Phase side by side. See differences in complexity, dice, genre, cost, and more.

	Call of Cthulhu	Eclipse Phase
Genre	Horror, Modern	Scifi, Horror, Post-Apocalyptic
Play Style	Investigation, Deadly, One-Shot Friendly, Atmospheric, Roleplay-Heavy, Mystery, Horror, Corruption, Skill-Based	Crunchy, Horror, Weird, Investigation, Espionage, Faction Play, Open Source
Core Mechanic	Roll d100 equal to or under your skill percentage. Success tiers at half (Hard) and one-fifth (Extreme) of the skill value. Bonus and penalty dice adjust the tens digit. Failed rolls can be pushed for a second attempt at greater risk.	Roll d100 and try to land equal to or under your skill (or aptitude × 3 for unskilled checks), adjusted by difficulty modifiers in ±10 increments. The 33/66 rule grades each roll on a single throw: a success of 33 or higher is a superior success, a failure of 66 or lower is a superior failure, and doubles (00, 11, 22, …) are criticals. Four pools, Insight (mental), Moxie (social), Vigor (physical), and Flex (wild card), spend to add +20 to target numbers, flip-flop a roll's digits, upgrade a success, ignore wounds or trauma, or introduce narrative elements like NPCs and environmental details.
Dice	d100	d100
Complexity	Medium	High
Accessibility	High	High
Runnability	Very High	Very High
License	Chaosium Fan Material Policy	Creative Commons CC BY-NC-SA 4.0
Cost	$$	Free (Quickstart) / $$
Publisher	Chaosium	Posthuman Studios
Year	2014	2019
Best For	Investigation-driven horror where combat is deadly and sanity is fragile. Great for one-shots.	Groups who want hard transhumanist sci-fi with cosmic horror undertones, dense subsystems for hacking and body-swapping, and the Firewall conspiracy framework where cortical-stack backups turn death into a setback rather than the end of a character.
Highlights	Tracking Sanity as a depletable score ties mental erosion to the fiction, so confronting cosmic horror mechanically wears characters down. The percentile skills resolve on a d100 roll-under, with Hard and Extreme bands at half and one-fifth of the rating. Bouts of Madness convert failed Sanity checks into temporary phobias, manias, or loss of character control.	The ego/morph split separates mind from body: characters back up their cortical stacks and can resleeve into biological morphs, robotic synthmorphs, or digital infomorphs between sessions, making body choice a tactical decision and death a recoverable setback. The 33/66 rule grades each percentile roll on a continuous scale of superior success or superior failure without rerolls, so a single throw produces a degree of outcome rather than just pass/fail. Seven distinct reputation networks (@-rep, c-rep, f-rep, g-rep, i-rep, r-rep, x-rep) replace cash for many transactions in post-scarcity territory, modeling factional standing as a parallel economy with its own favor limits and weekly refresh caps.
Considerations	The chase rules add a detailed positioning subsystem whose complexity outweighs how often it sees use. Character creation allocates points across a long list of skills, a slow first step for new players. In long campaigns the sanity spiral can strip a character of player control as madness accumulates.	Bookkeeping splits across an ego sheet (mind, skills, traits, pools, rep) and a separate morph sheet (body, ware, Durability, derived combat stats), and resleeving mid-campaign swaps out the morph half including pool maximums. The book takes an overtly political stance: the introduction states it is "not the game for you" if you support authoritarianism, and faction writeups present anarchist and autonomist values as the authorial baseline rather than one option among many. Routine cortical-stack backups make character death recoverable by design, so traditional life-or-death stakes need to be reframed around backup destruction, exsurgent infection, or memory lack to carry weight.