The game has been out of print since about 1983 when Howard Thompson, the owner of Metagaming, closed the company and Jackson was unable to secure the rights to the game. In 2005, Dark City Games, Inc. began publishing additional supplemental material for the game, without input from Thompson or Jackson.
Strength (ST): determines how much a character can lift, how heavy a weapon he can wield and how much damage he does. This stat doubles as hit points and spell fatigue points (e.g., a wizard with ST 11 has 11 hit points and can spend 11 fatigue points to cast spells).
Dexterity (DX): controls how well characters perform agility related actions, including combat. This stat is used for both manual dexterity actions (e.g., picking locks) and physical actions (e.g., climbing and jumping). Armor reduces dexterity.
Intelligence (IQ): controls the number and complexity of skills and spells the character can know. This stat also doubles as perception and willpower (e.g., disbelieving illusions).
Base human characters are created by starting with a base of ST = DX = IQ = 8, and adding 8 points as desired. Other races, such as Elf, Dwarf, Halfling, Lizardmen, etc. are provided, each of which has different starting stat levels and special abilities.
Each skill costs between 1 (easy) and 3 (hard) IQ points to learn. Each skill has a minimum IQ to learn, and may have other prerequisites. Spells costs 1 IQ point to learn.
Most actions are resolved by rolling 3D6 against the governing attribute (e.g., vs. ST to lift a heavy object, vs. DX to hit with a weapon, or vs. IQ to notice a concealed object). If the total of 3D6 is less than or equal to the attribute, the action succeeds. The base chance to succeed and/or the number of dice rolled to succeed can be modified to simulate actions which are easier or more difficult than normal.