Numenera
DiscoveryCore Mechanic
GM sets task difficulty 1–10; the target number is difficulty × 3 on a d20. Players ease difficulty by being trained (one step) or specialized (two steps) in a skill, having a favorable asset, or applying Effort — spending points from Might, Speed, or Intellect Pools, with Edge in the relevant stat reducing the cost. Players make all rolls; defense rolls against creatures use the same d20 system as attacks. Natural 17–20 add bonus damage or trigger minor and major effects; natural 1 prompts a GM intrusion that awards the player XP.
Best For
Groups who want exploration-driven science-fantasy where uncovering ancient technology and forgotten knowledge is the campaign's core reward. Particularly suited to GMs who prefer minimal preparation and players who enjoy spending stat-pool resources to ease tasks rather than tracking many subsystems.
Highlights
Cyphers are single-use, randomly determined gadgets that every character carries and that refresh each session, so combat and problem-solving options change constantly without permanent power creep. The GM never rolls — players make all attack and defense rolls against fixed creature target numbers. Three character types (Glaive, Nano, Jack) combine with dozens of descriptors and foci to produce sharply differentiated builds without a class-and-level structure. XP is awarded for discovery and for accepting GM intrusions rather than for combat, and players can spend XP on player intrusions to bend the narrative.
Considerations
Combat is theater of the mind by default with no grid or detailed positioning rules. GM intrusions are central to play and require player buy-in; players who prefer uninterrupted action control may find them disruptive. Cyphers must be rolled or selected fresh each session, adding GM workload that scales with party size. The Ninth World setting is intentionally vague in many places, leaving GMs to invent specific details.