Chaosium's Basic Role-Playing (which I've lauded previously) was extracted from the rules of RuneQuest, simplifying and genericizing them in order to serve as a foundation for other RPGs. The first game to explicitly do so was 1981's Call of Cthulhu, whose rulebook, unlike that of its contemporary Stormbringer, referred back to Basic Role-Playing for an understanding of certain foundational mechanical concepts. BRP was thus intended as a "high level" document, establishing only the most basic principles of the game system, such as characteristics and skill rolls, while individual games dealt with the specific details of expanding upon those principles.
1982's Worlds of Wonder was another step along the road to showing how Chaosium wanted Basic Role-Playing to be used. This boxed set came with four short booklets (three are 16 pages in length and one is 18 pages). The first is BRP itself, while the other three each presents a different "world" (i.e. genre) in which to use the rules of Basic Role-Playing, complete with all the rules needed to play. Of course, "complete" is a relative term and there's no question that by most standards (even back in 1982), the world books were more like the skeletons of games rather than fully-fleshed out, ready-to-go games. Consequently, Worlds of Wonder has an "experimental" feel, as if Chaosium were testing the waters to see if how much BRP could be stretched beyond its roots in RuneQuest.
The first of the three world books is Magic World, a fantasy game that is reminiscent of a between a de-Glorantha-ized RQ with some nods toward Dungeons & Dragons. Not huge nods, to be sure, but Magic World is very traditional in its presentation, largely lacking the idiosyncrasies that make RuneQuest so appealing to its fans and frustrating to its detractors (and might-have-been fans). As a BRP derivative, it's skill rather than class-based but starting characters must choose one of three "professions" -- warrior, rogue, or sage -- which determine the starting skills to which the character has access. Interestingly, the default assumption is that a new character is a rogue, as it has no entrance requirements, while becoming a warrior or a sage requires a roll to be accepted for training.
As in RuneQuest, new skills are acquired through training (which costs money), while old skills are improved through use. Magic is potentially available to all, but it requires admittance to the Sorcerer's Guild to learn (again, with entrance requirements). The selection of spells is small and somewhat bland (compared to RQ, CoC, or Stormbringer anyway). Spells are divided between sorcery and ritual magic, with the former being magic one can cast on-the-fly and ceremonial magic requires greater time, expense, and concentration. Magic World includes a small selection of monstrous opponents, pretty demanding that referees either create their own or swipe them from other BRP games.
Future World is the longest -- and densest -- of the three world books, presenting a science fiction world in a "galactic empire" vein, with the PCs assumed to be agents of ICE -- the Imperial Corps of Engineers, which, despite its name, is in fact an eclectic collection of troubleshooters for the Empire. Like Traveller, Future World characters begin play with prior experience. However, there's less randomness and more breadth to this prior experience, with players choosing which skills they wish their characters to have and the ability to switch professions multiple times, thereby allowing "cross training." Like Magic World, there are still entry requirements for certain professions, meaning that character generation is still somewhat at the whim of dice rolls.
Several sample alien races and robots are presented, as is a great deal of equipment. Combat and other mechanics receive some large expansions, mostly due to the highly technological nature of weaponry. There are no starship rules -- travel is assumed to be via gates and ICE missions are all planet-bound, it seems -- or any planetary creation guidelines. There is a sample adventure included, which is odd, given its length (nearly five pages), which in my opinion could have been more profitably spent on including a few other sub-systems of use to science fiction gaming. Far moreso than Magic World, Future World very much feels like a sketch of a game rather than a complete game in its own right.
Superworld (which would later be expanded into a full game of the same name) is a BRP treatment of the superhero genre. Characteristics are still rolled randomly, but any one that is below 11 is given a +3 bonus to bring it more in line with the expected level of character power. Adding together one's characteristics gives a pool of "hero points" with which skills, superpowers, and even characteristic boosts can be purchased. Hero points can also be spent on "energy points" by which superpowers function. More hero points can be acquired through taking on "disabilities" or in some way limiting a character's superpowers -- all standard fare for superhero RPGs.
Superworld describes about 30 powers, many of which are quite broad and in fact encompass several sub-powers. Combat receives some modifications in order to better simulate four-color action (with knockback, etc.), but is still very much in line with BRP's assumptions. There's a very short sample adventure (more a slugfest than a true scenario) and some notes on various topics of interest (referee's advice more or less). Also included are some designer's notes by Steve Perrin, who explains that Superworld grew out of his dissatisfaction with Superhero 2044, which he found contradictory and unsatisfactory to his needs.
Worlds of Wonder was an ambitious project and one whose results were mixed. All three of the worlds have elements to admire, but, as I've said, they all require some amount of work on the part of the referee and players to become "proper" RPGs. For many, this is undoubtedly a plus, but, then as now, I suspect that many will lack the interest in becoming a "co-designer" with the good folks at Chaosium just to play science fiction or superheroes. Still, I can't help but think that Chaosium's approach of having a very basic -- in the "foundational" sense of the term -- set of core rules, with each game built on their foundation adding specific complexities, is a better approach than a huge, sprawling "generic, universal" philosophy. Games like HERO and GURPS simply hold no appeal for me, especially nowadays, whereas Basic Role-Playing's appeal is increasing, in part, no doubt, to its genuine elegance. It's a simple, straightforward system that's surprisingly robust and flexible, as Worlds of Wonder makes abundantly clear.