A Brave New World…

…complete with people like a four-eyed flying monkey, a three-armed cat-man, an ambulatory vine that throws exploding seeds, a dark-skinned female human with gills who stands over eight feet tall, a normal looking man who levitates and controls the actions of those he touches, and a small rusty-looking cyborg who enjoys taunting computers and lesser robots. Maybe they need to recover healing fruit from an ancient building with an overgrown arboretum, or maybe they are helping a farmer learn what’s killing his six-legged blue sheep.


This is the Gamma World – a futuristic RPG set on earth after the ravages of nuclear and biological war. Mutants (creatures changed by radiation, genetic modification or biological effects) are common, as are the artefacts of the pre-war society – some undamaged and functional, others ruined, broken or decayed. Humans are either the descendants of those who lived through the worst in bunkers, were frozen embryos or clones (Pure Strain), or “altered” – those who survived, but aren’t entirely human any more. Larger, sentient animals exist, many with mutations or defects. Robots and AI’s, some functional, others with damaged programming and memory loss can be encountered, along with mobile intelligent plants.

Gamma World, first produced by TSR in 1978 is now into its seventh edition. I was first entranced by the idea of this game from three pages in my 1979 Advanced D&D Dungeon Master’s Guide which described converting D&D characters to and from the “Boot Hill” and “Gamma World” game systems. I didn’t get to play until the late 1980’s, when at University I started a short 1st edition game. One of the guys in my gaming group ran a short 3rd edition campaign in that time too. I bought the 4th edition when it came out (TSR 1992) – loved it, but never played it. (It’s mostly based on 2nd edition D&D rules, but looking back it’s obviously a precursor to 3rd edition, with defined class skills, DC’s, three saving throws, etc.) A friend gave me a copy of the Player’s Handbook for the sixth edition of Gamma World (2003) and this got me interested again. This is a d20 version produced by ‘Sword & Sorcery’ with three hardback rulebooks and three supplements, mostly based on d20 Modern and requiring that rulebook. It’s very good at defining the world and background, but has a lot less mutations and equipment than earlier versions.

The “people” of the Gamma World mentioned at the beginning are sample characters I created with my new system for play testing with my gaming group. Both sessions have been a lot of fun, and helped my tweak my rules and tidy up skills and abilities. I’m nearly at the stage where players could create their own characters with the rules.

I’ve considered merging the rules presented in both the 4th and 6th editions for a long, long time… this year I actually started doing it. The fourth edition allows plants as character races, has 102 mutations and 18 defects, and about 40 pages of equipment, weapons and artefacts. The sixth edition has no plants, but allows “synthetics” – robot player characters, 45 mutations (about half are defects), about 20 Cybernetic/Psionic powers, and only 18 pages of equipment. My system – I’m calling it 4.5 – is based mostly on the 4th edition material converted to d20 (3.5 D&D), drawing from Pathfinder, d20 Modern and of course the parts I like from GW 6th edition.

One thing I never liked about early GW versions was the randomness of mutations. You could have one character who was really powerful (laser eyes, immunities, regeneration) and another with bad eyesight, three legs and ability to levitate small rocks. No balance. Unless it was a campaign where you expected to die quickly and make up another character, it could be really annoying. My system gives most genotypes a number of points to buy mutations. Each mutation costs one to three points. You roll on a table, if you can afford the mutation you take it, or you roll again. If you choose to take a 1 or 2-point defect, you get extra points for good mutations. During game-play, radiation exposure may randomly grant 1 or 2 points of good or bad mutations. At character creation, it’s a choice.

I have five Genotypes – Pure Strain Humans, Altered Humans, New Animals (15 subtypes), Green Folk (6 plant subtypes) and Live Metal. There are ten base classes: six from d20 Modern (Strong, Fast, Tough, Smart, Dedicated, Charismatic) and four from 4th/6th edition – Enforcer, Esper, Examiner and Scout. All of these have been adjusted to balance out more evenly than their d20 originals. My skills list is mostly based on Pathfinder with some GW/d20 Modern additions, with revised or new descriptions when required. I have 30 fully detailed skill descriptions, 78 Class Abilities, and 100 Feats.

I’m currently converting all the 4th edition mutations to my d20 version, and then I’ll add in some of the powers from 6th edition. Equipment will be predominantly from the 4th edition and I mostly need to make range adjustments (from metres to feet), and “monsters” from the 6th edition almost as is.

Once it gets a bit further along, I’ll put detail up on my Resources page.

Have you ever played Gamma World?   What edition did you play and would you play again?