Gamma World vs The Expanse Roleplaying Game

Compare Gamma World and The Expanse Roleplaying Game side by side. See differences in complexity, dice, genre, cost, and more.

	Gamma World	The Expanse Roleplaying Game
Genre	Post-Apocalyptic, Scifi	Scifi
Tags	Superpowers, Random Character Creation, Classless, Gonzo, Comedy, Tactical, Grid-Based, Combat-Heavy, Beginner-Friendly, Deadly	Licensed IP, Space Opera, Ship-Based, Crunchy, Social Combat, Investigation, Faction Play, Social Intrigue, Strong GM Support, Tactical
Core Mechanic	Roll a d20 and add a modifier, then compare the total to a target number or one of four defenses: Armor Class, Fortitude, Reflex, or Will. Two randomly rolled character origins combine to set starting ability scores, skills, and powers instead of a chosen race and class. Alpha Mutation and Omega Tech cards drawn from a shared deck grant each character's most powerful and unpredictable abilities for the session.	Roll three six-sided dice, two matched and one differently colored Drama Die, and add an ability score plus a focus bonus of +2 if applicable. The total must equal or beat a target number set by the GM or an opponent's result. Rolling doubles generates stunt points spent on combat, exploration, or social effects. The Drama Die's value sets the degree of success.
Dice	d20	3d6
Complexity	Medium	High
Accessibility	Medium	High
Runnability	Very High	Very High
License	Proprietary	All Rights Reserved
Third-Party Publishing	Not yet researched	No verified route found
Summary only, not legal advice. Check current terms before publishing.
Cost	$	$$
Publisher	Wizards of the Coast	Green Ronin Publishing
Year	2010	2019
Languages	English	English
Best For	Groups who want a silly, fast-paced pickup game with randomly generated mutant heroes rather than a long-term character build.	Groups who want a character-focused science fiction campaign of crew jobs, faction pressure, and danger across the Solar System. It suits tables that want structured action, investigation, and social encounters alongside ship travel.
Highlights	Alpha Mutation and Omega Tech cards replace a fixed power list, so a character's abilities shift unpredictably as cards are drawn, used, and discarded between encounters. Rolling two random character origins instead of choosing a race and class produces unplanned combinations that push players toward improvised character concepts. A hundred-item Ancient Junk table turns ordinary scavenging into a steady stream of small, flavorful rewards between the rarer Omega Tech finds.	Backgrounds, professions, talents, and focuses build characters with mechanical ties to their lives before the campaign begins. Action, exploration, and social encounters each use dedicated stunts, giving different kinds of scenes procedures beyond a single skill roll. The Churn turns accumulated complications into escalating story events, giving the Game Master a structured way to introduce setbacks.
Considerations	Character origins are rolled randomly from a fixed table, so a player who wants a specific concept must ask the Game Master for permission to choose origins instead. The starter box's 80 cards are the only power pool for groups without the two out-of-print expansion kits, capping how many distinct Alpha Mutations and Omega Tech items a table can draw. Running combat means tracking multiple readied and discarded card piles for each character in addition to the four defenses, conditions, and forced movement of the underlying 4th Edition engine.	Combat stunts are drawn from six separate category tables covering roughly sixty options, requiring both players and the GM to check charts mid-fight to keep pace. Ground and air vehicles receive no example statistics, leaving their combat rules almost entirely improvised. The forty-page setting guide summarizes the solar system's factions and history at a survey level, so groups wanting deeper political detail need outside reading of the novels.