Here's what I'm doing, It's a combination of House rules, some cribbed and expanded from Dark Sun, and a set of cards and handouts for the players.
The Equipment cards are for for generic stuff that the players may find/use/trade. I have cards for:
Guns - Heavy/light, one/two handed
Ranged & melee weapons, Heavy/light, one/two handed
For the assorted generic salvage cards, they all have numbers 1-9, and when they are used to fabricate/trade/repair if you want you can roll a d10 to see if you have "just the right thing" and get a bonus of some sort to the action.
For the wound cards, if you are going to use the rules below, print out as many Wound cards as you could expect to show up in a really bad combat, and as many Lingering Wound cards as you want for a nice random draw with chances of stacking penalties, I had a pack of sleeves for them, so I printed out 9 sheets of Lingering Wound cards for a deck of 45, I don't expect to use that many of course.
Tallyrand's House Rules for GAMMA WORLD
CHARACTER CREATION: The way I have this allows the players to choose the origins they want for their characters, but it rewards them for rolling them randomly.
1: Pick 2 Origins, 1 Primary, and 1 Secondary, then roll remaining Attributes straight down with 3d6
2: Roll one Origin, and choose the other, assign Primary and Secondary and either roll remaining attributes straight down with 4d6 dropping the lowest die, or roll 3d6 for remaining attributes, assigning them where you choose.
3: Roll both Origins, assign one Primary and one secondary, then either roll 4d6 dropping the lowest die for remaining stats, assigning them where you choose or roll 5d6 dropping the two lowest straight down.
LITERACY: Reading and Writing have fallen by the wayside since the Big Mistake, and books are just another source of kindling to some. If you choose, at character creation, you may make your character illiterate, this may cause some problems down the road, but hey, you can't help the way you were raised. If you choose to be illiterate, you must be doing something with that extra room in your head, so whenever you draw Alpha Mutations, you may draw one additional card and return the one you don't want back to the bottom of the deck.
WOUNDS: The world is harsh and unforgiving, the result of fighting is that you get hurt, and the only thing that can help you is rest and some medical attention. These aches and pains are represented by Wounds and Lingering Wounds. You take a Wound in combat:
-The first time you are bloodied.
-Each time you fall below 0 hit points.
-Each time you fail a Death Saving Throw.
-Whenever you take a Critical Hit – Minions deal no Wounds on a Critical Hit, regular monsters deal 1, elites 2, and solos deal 3 Wounds on a Critical Hit.
Wounds give the character a cumulative -1 penalty to all Attribute and Skill Checks.
At the end of combat, after a short rest you make a saving throw for each Wound you have taken, a success means the wound is discarded, a failure means the Wound becomes a Lingering Wound. With a Hard Constitution Check, or a Hard Science Check for First Aid you can get +2 to your saving throws. You only have time to make one Science/First Aid check for yourself or someone else during a short rest.
Lingering Wounds give the character a cumulative -1 penalty to all Attribute and Skill Checks, as may give cumulative penalties to Speed, Defenses or To Hit Rolls.
At the end of an extended rest, you automatically heal one Lingering Wound. After that you may make Hard Constitution Checks or Hard Science/First Aid checks to remove each of your remaining Lingering Wounds. There is enough time during an extended rest for one person to tend to everyone's Lingering Wounds with Science/First Aid. When healed of Lingering Wounds, the player may choose which Lingering Wounds are discarded.
SURVIVAL: Just about everyone needs food and water to get by, and some need more than others. Except for those noted below, everyone needs one ration of food and one gallon of clean water every day to get by. The exceptions are:
Android – Needs neither food nor water to survive
Cockroach – May drink Dirty Water without penalty, and may declare rather questionable things to be “rations”
Giant – Needs double food and water rations
Plant – If exposed to sunlight for just one hour a day, it does not need a food ration
Radioactive – May drink Dirty Water without penalty
Rat Swarm – May drink Dirty Water without penalty, and may declare rather questionable things to be “rations”
Speedster – Needs double food rations
Failure to meet your survival needs has penalties, if you don't meet your needs for a day then at the end of the extended rest Science/First Aid may not be used to cure your lingering wounds. Additionally you start the next day with additional lingering wounds if you did not meet the previous day's survival needs:
Did not eat a Food Ration +1 Lingering Wound
Drank Bad Water +1 Lingering Wound
Did not drink at all +2 Lingering Wounds
WEAPONS BREAK: Let's face it, most weapons are junk, if you are going into battle with a meat cleaver duct taped to a baseball bat, it's not going to last forever, and even a well preserved handgun in Gamma World is still over 150 years old. Any time you roll a natural 1 on your attack roll with a non Omega Tech weapon, if you wish, you can push it, and re-roll your to hit. But hit or miss, the weapon you are using breaks becoming a piece of useless junk.
That's all I have, I'm hoping for a fun wacky game, but I still want there to be a survivalist aspect to it as well.