This game is set on Earth in the future, following a nuclear disaster. AlphaMan is a mutated human (name and gender chosen by player) who is struggling to save the planet from complete annihilation.
AlphaMan has a deliberate lighthearted feel to it, and make a lot of pop-culture references.
The ultimate goal of the game is to locate the Grinch's stronghold and beat this powerful and psychotic enemy. To do so, you must first enter five other castles and beat the respective bosses there, each time gaining an indispensable item. The name of these bosses and castles shows a pop-culture references, like Gilligan in the castaways' fortress, and Buzz Aldrin, cult leader of These Who Came In Second.
This game uses colorful text-based graphics in the spirit of Rogue or NetHack, and uses many of the 1st edition Gamma World rules wholesale. You will be pitted against hideously mutated plants and animals, traps and snares of all sorts, and several varied adversaries whom you will have to defeat in order to complete your mission. At your disposal are a broad variety of technological relics and mutated substances which you will acquire along the way, as well as your own powers and guile.
As a character progress, (s)he will accumulate technological relics which can be extremely useful. AlphaMan includes over 125 different devices, including tech weapons like the Laser Pistol, Flamethrower, etc., various grenades, vehicles like the Hovercraft or Golf Cart, protective suits like the Radiation Suit or the Bulletproof Vest, and a myriad of miscellaneous gadgets.
Many devices one can find are truly useless, such as the Toaster or Leafblower. Some have more subtle uses. A Microwave Oven, for example, can prematurely ripen berries (see below). A Home Movie Projector will put critters to sleep. Some devices can be dangerous to use, like the Porta-Potty or the Kevorkian Machine. Some devices are of obvious use, such as the Medkit, which will restore lost hit points and remove the detrimental effects of poison. One particularly useful device is the Microcomputer (or the Computer Workstation) which can be used to reveal a variety of information about weapons, berries, devices, creatures, etc.
Mutated berries provide a variety of effects, and can be eaten or thrown depending on the type of berry. AlphaMan includes over 30 different types of berries which do things like turn you invisible if eaten, heal lost hit points, explode, etc. What a particular berry will do is generally not known until that particular type of berry has been eaten (or a Chemical Analyzer has been used on it), so some dangerous eating experimentation must generally be done. Some berries, if thrown at other creatures, will reveal their nature that way (you may, for example, toughen the skin of the creature or turn it invisible).
You can occasionally find nectar or extract as well (or make it from a berry using a Still); these are more potent versions of berries.