The setting is the generation ship Warden which flew through an unexplained radiation cloud that killed off the crew and most of the colonists. Over hundreds of years the ship's surviving colonists have lost most knowledge about their technology and have mutated into strange new forms of life. The players create human and mutant characters that explore their world, and possibly eventually take control of the Warden.
The game's rules set is a variation on the original edition of Dungeons & Dragons, with different attributes and character options but very similar combat rules. The biggest departure is that there is no Class and Level System and there are no real provisions for character advancement other than gathering treasure and followers together.
This Game Contains Examples of:
- Auto-Kitchen: Gygax magazine #3 adventure "They All Died at the International Space Station". One room of the space station is a luxury apartment for a wealthy person on holiday. It has an automated kitchen that can create meals for the guest.
- Barbarian Tribe: Most humans are part of one of these to begin with.
- Colony Ship: Only a fraction of the colonists survived the radiation cloud. Originally there were 1,500,000 colonists, and 50,000 crew members.
- Dungeon Crawling: The Warden is basically one massive dungeon IN SPACE!!
- Everything Trying to Kill You: There is a fairly extensive list of mutant plants and animals that inhabit the Warden in the rules, nearly all of which are lethally dangerous.
- Generation Ships: The Warden itself is a massive generation ship.
- Humans Are Leaders: Only human characters have the Leadership Potential attribute, which gives them a chance to recruit followers. The rules explain that mutants all distrust each other too much to allow a fellow mutant to lead them anywhere. Leadership potential is also used to understand items of Lost Technology, which gives players two very good reasons to have at least one un-mutated human in the party.
- Lost Technology: Following the dungeon crawl model, lost technology items are the "magic items" players can discover and use.
- Mutants: All of the monsters encountered are mutants of life forms originally brought aboard the Warden for the colony. Playing a mutated human, plant, or animal are all options. Dragon magazine later added rules for playing robots and clones.
- Mile-Long Ship: The Warden is the only environment in the game, so it has to be big enough to explore. The introduction to the game gives its dimensions as 50 miles long, 25 miles wide, and 8 and-a-half miles high, with 17 decks.
- Negative Space Wedgie: The radiation cloud that caused the disaster on the Warden. It caused most people to turn into piles of calcium with no advance symptoms, mutated the surviving flora and fauna, and affected the ship's systems.
- Nuclear Nasty: All of the monsters on the Warden are the results of earth animals or plants having mutated from unusual radiation.
- Radiation-Immune Mutants: Every character had a "Radiation Resistance" trait, which means some mutants are more immune than others.
- Random Encounters: The game contains encounter charts and rules to checking for wandering "monsters" every hour while wandering through the ship.
- Recycled IN SPACE!: It's basically the D&D ruleset re-purposed for a sci-fi setting. The rear cover even says "In the Tradition of Dungeons & Dragons".
- Spiritual Successor: The later Gamma World was very much Metamorphosis Alpha set on Earth After the End.
- The Six Stats: The six stats in this game are Radiation Resistance, Mental Resistance, Dexterity, Constitution, Strength, and Leadership Potential, all generated by the traditional 3d6 roll. Mutants don't have Leadership Potential, gaining 1d4 physical and 1d4 mental mutations (and at least one defect) instead.
- Ur-Example: Possibly the first Sci-Fi RPG, and certainly better known than the contemporary Starfaring.