Published in 1978 by TSR and written by James M. Ward and Gray Jaquet, Gamma World is a Science Fantasy Roleplaying Game centered around PC surviving in a nuclear wasteland as they scrounge for technology from the ancients, use their mutant powers to fend off monsters, and try to keep the local Secret Organization off their backs.
Before getting into my initial thoughts on Gamma World 1e, I would like to disclose that I purchased a Print-on-Demand copy of the rulebook and have not had the chance to run the system. I do not have system mastery and will likely overlook certain details that likely would meet certain issues or concerns I might have.
The first thing that greets you upon getting the book is a nice color cover featuring a team of soldiers in Astronaut gear wielding laser rifles and gizmos as they head into an overgrown and ruined city. Opening the 54 page book, the Gamma World rules greets you with the iconic, black and white image of the Mutant Monkey holding a pistol at the monster.
The pages after the Introduction covers everything you need to know to build the world, make a character, run the game with examples of the game in action to help get started. Though, these 54 pages are fairly dense with blocks of small text only broken up by headers, a couple of piece of art, the matrixes used for combat and the tables of used for Artifacts, treasures and monsters depending on the terrain the PCs are currently in. In the back of the book are all the tables and matrixes that would be needed to be referenced during play.
Reading over through the rulebook, it's a fairly dense read, but once you've read a small paragraph a couple of time and been able to mull over the text for a little bit; the rules make enough sense that you can run a game with them. Though, like any rulebook from TSR, reading the rules over a couple times is always a good habit to make sure your own sanity is in-line with the sanity found in the rulebook.
In these readings, the only thing I think I saw missing was a table for Modifiers from Ability Scores, but I might be missing something myself or it might be present in one of the two modules (Famine in Far-Go and Legion of Gold) as a late addition. Though, this isn't knock against the rulebook since (if memory serves), the AD&D DMG held rules for converting characters to and from games like Boothill and Gamma World; which means the Ability Score Modifier table could be ported from AD&D easily without breaking a whole lot.
I hope to run Gamma World for my home group. Its a system that's been on my radar for a little while now and now it's likely going to chew at me until I get a chance to run it.
For a more comprehensive overview of the rules, go take a look at the review made by capcorajus here.