The Gammarizer: Bringing Your Town to Gamma Terra

The Gammarizer is my attempt at a semi-random adventure generation tool for Gamma World. You start with a location all the players are familiar with (like your hometown) and then change it to fit into the post-apocalyptic setting of Gamma Terra, and in the process, generate an adventure on the fly. This method focuses on using the elements of a setting and altering it to connect to the origins of the PCs to give it that Gamma flavor and a personal connection.

To begin:

  1. All the players decided on a setting that everyone at least has a passing familiarity with.  (For example, Westminster Maryland.)
  2. Gammarize the name. (Questmonster.)
  3. Each player writes down on an index card one element of that setting to start with. This can be specific or general. (McDaniel College, plentiful corn fields, Main Street, and cows are all possibilities.) These should be kept secret except to the GM, and duplicates are fine.
  4. The GM shuffles the cards out and gives one to each player. It’s OK if players get their own.
  5. Each player writes down on the card a way that connects that setting to one of their own origins. (A radioactive ratswarm may say that the corn fields are irradiated or filled with rats.)
  6. The GM takes the cards and builds the adventure. If something immediately suggests itself based on the cards, great. Otherwise, try taking the cards, and assigning (either randomly or by selecting) one to be a setup/hook, two to be encounters/scenes, one to be a complication, and one to be the climax/finale.
  7. Make adventure go.

I ran a test of this over the weekend, and I’d say it was a big success. The PCs all provided me with very good seeds to start with, and the nature of Gamma World makes it easier to gloss over any leaps of logic (“of course you can negotiate with the pile of cats” “of course a gravity cannon can turn a park into an army of mutant plants.”)

However, I essentially made a villain that was separate from all the cards, and pulled from my own imagination based on the off-hand comment by one of the players. So be prepared to either have some stock villains ready, or take a strong look at the adventure seeds for a villain specifically. Like they tell you in the Dungeon magazine adventure guidelines, the villain is often the one that drives the action, so keep an eye on that while you build your adventure from those elements.

Encounter design is also an important part to keep your head wrapped around. I had both the GW guide and Monster Vault ready, and dipped into both. As always, re-skinning is your friend, especially among the bizarrely specific Gamma World bestiary. Gamma moths became sentient silverfish, giant razor beetles became giant plants, and fire elementals became extradimensional summoned plasma creatures. Due to the swingy and brutal nature of GW combat, I didn’t worry as much about exactly balanced combats (to be honest I never do in D&D either, though usually in the opposite direction) as a few level 1s and a level 4 can always end up doing more damage than intended. It would be much easier to manage if there were a GW equivalent of a Compendium to print out individual monsters, but in the absence of that, use your own organizational method to make encounters go a bit smoother. I also seriously hurt for more poster maps in GW, since I am abysmally bad at drawing maps. Hopefully when the two expansions come out that will be helped somewhat.

While I may be a pretty experienced GM and now have a strong handle on Gamma World, I’m not a strong improviser of games from scratch, so I was a bit worried about how the game would run. I was fortunate enough to receive some great pieces to work with from my players which helped a lot. Just remember that these are only suggestions, and you should feel free to adjust them as you see fit to create the best story. Surprising a player with something based on what they had written is a satisfying experience by itself.

If you’d like to read a play report of how the first Gammarizer session went, you can read it over on Roll. With the Gammarizer developed, I can now turn my attention to the two Gamma World games I need to plan for DDXP.

About Dave

Dave "The Game" Chalker is the Editor-in-Chief and Co-Founder of Critical Hits. Since 2005, he has been bringing readers game news and advice, as well as editing nearly everything published here. He is the designer of the Origins Award-winning Get Bit!, a freelance designer and developer, son of a science fiction author, and a Master of Arts. He lives in MD with e, their three dogs, and two cats.


  1. Very interesting idea. If we at last have time for GW this weekend – I’ll definetely try it.

  2. An idea that we used to some success – grab some free town maps from the chamber of commerce or wherever, then use them as navigation aids for the Gamma version of your city. If you don’t have that option, then I’d say the web map application of your choice would do. A big black marker, some strange symbols or cryptic messages, a little dirt and some torn corners and you’re set!


  1. […] and actually try to develop some kind of campaign setting. Prior to the game, I decided to give The Gammarizer a try (thanks to Critical-Hits for this awesome idea!) Instead of using our hometown, we actually […]