Challenges appears to have been self-published by Moldvay through a company called "Challenges International Inc." It's a thin booklet consisting of 8 pages of rules and charts, some endpapers, and a cover. In its brief introduction, Moldvay explains that Challenges
offers an easy-to-play alternative to fantasy game systems which are becoming increasingly complex. All of the basic information needed for play is organized into 8 pages instead of scattered among hundreds of pages of several expensive books.I liked the cut of Moldvay's jib to begin with, but this introduction only increased my affection for him. Succinct and without pretense, the introduction is unambiguous on the side of those who see published rules as guidelines for the creation of a roleplaying game fashioned to one's own taste.
The Challenges Game System is intended to be a foundation. Game Masters and players can add whatever they like to the system. They can change any rules they want. But the 8 page guide will still remain a basic reference aid, a place where essential information can be quickly found.
Of course, reading through Challenges, it's also unambiguous that Moldvay is taking aim at late era AD&D 1e. The system presented in its 8 pages is largely identical to that of AD&D (with a few interesting wrinkles), stripped down to its essentials and presented far more coherently. Characters have six ability scores: Muscle, Dexterity, Stamina, Willpower, Wisdom, and Charisma. These are generated by rolling 2D6+6 nine times and choosing the best six rolls, arranging them as desired ("Player characters are heroes, not average individuals," Moldvay notes to my disappointment). Scores of 18 -- which would be more likely under the suggested method of random generation -- get a further percentile roll to distinguish them, much like exceptional Strength in AD&D, except that it applies to all ability scores. Ability modifiers are not rationalized -- they vary by ability -- but, outside of the highest percentile scores, they're fairly small, generally +1 or +2.
Challenges presents five classes (warrior, sorcerer, cleric, thief, and mirager -- an illusionist) and five races (humans, dwarves, elves, gnomes, and hobbits, the latter of which Moldvay claims is based on "British folklore" and makes no reference to Tolkien whatsoever). Races are mostly cosmetic in their differences, with a few gaining special level-dependent detection abilities, infravision -- yes, that term is used -- and, in the case of dwarves, a penalty to Luck rolls, which is the Challenges equivalent to saving throws and is a single score, as in Swords & Wizardry. Classes are simple and straightforward in their presentation, with individualized XP charts. Characters start with maximum hit points (+ Stamina bonuses, if any). Thief abilities are generalized into "Thief Skills" and "Stealth," each governed by a level-based percentile score. Spells are highly simplified -- a line or two description reminiscent of OD&D's presentation.
Combat is where Challenges differs intriguingly from AD&D. All classes have a base attack number, which is what they must roll on 1D20 to score a hit, thus eliminating the need for combat charts. This number is modified on the attacker's side by Muscle or Dexterity, as appropriate. On the defender's side, it's modified by Dexterity and armor. Initiative, however, is a simple 1D6 affair, modified by Dexterity. As optional rules, the amount by which a character exceeds or misses his target number can have additional effects, from bonus damage to dropping one's weapon. Bonus damage also introduces the concept of "wounds," which are persistent combat penalties until healed in order to simulate injury without overly complicating the system.
Challenges also includes rules for turning undead, monster attacks, and multi-classing. It lacks any rules for equipment beyond armor and some basic weapons and includes no example monsters or treasures, the implication being that most of these would be described in adventure published for the game. So far as I know, there was at least one, possibly two, such adventures published, but I have never seen them, so I cannot comment on their contents. As presented, Challenges is not quite a complete system, but, if one has other D&D materials handy, it'd be easy to fill in the gaps.
I suspect that's what Moldvay assumed players would do, which does make one wonder why he bothered to produce this guide book at all. That's not a knock against Challenges, to which I am rather favorably disposed, but I wish I knew more about the circumstances under which this RPG was produced and what Moldvay's plans were for it. As it is, it's close enough to AD&D that I'm not sure it'd stand up to an assault by TSR's legal department, so what was he thinking? On the other hand, as a distillation of AD&D -- a kind of "AD&D Lite" -- it's quite well done and a reminder of how, in practice, many of us played 1e. Nowadays, I have Labyrinth Lord and the Advanced Edition Companion, so there's little need for something like Challenges, but Moldvay was doing this in 1986, years before anyone else. It's a fascinating historical artifact and a reminder to me, as if I needed one, that Tom Moldvay was a clever and imaginative guy and it's a pity he doesn't get lauded as often as he most assuredly deserves.