After WEG was acquired by Purgatory Publishing they released in 2003-2004 updated version of the generic D6 System with minor tweaks, and split them by genre. The results became D6 Adventure, D6 Fantasy, and D6 Space.
Read the Unofficial History of the D6 System.
Attributes and skills
Characters in the D6 System are defined by attributes and skills. Attributes represent the raw ability of a character in a certain area. Most D6 System games utilize anywhere from six to eight attributes, though these can vary greatly in number and name by the game in question. Acumen, Intellect, Knowledge, Perception, Presence and Technical are examples of mental attributes; Agility, Coordination, Mechanical, Physique, Reflexes and Strength are examples of physical ones. Skills are the trained abilities of the character and are associated with a specific attribute (e.g., driving, acrobatics, and climbing might be skills based on the Reflexes attribute). Each attribute and the skills under it are rated in values of Dice and Pips; Dice equal the number of dice rolled and Pips equal a one or two point bonus added to the roll to determine the result. The more dice and pips in the rating the better the character is at that skill or attribute. A character with a Strength rating of 4D+2 is stronger than a character with a Strength rating of 3D+1, for example.
Actions and resolution
Character actions are resolved by making dice rolls against a difficulty number. There are two types of difficulties, standard and opposed. To perform a standard difficulty action, the gamemaster calls for the player to roll the dice for a certain attribute or skill. The value of each die is totalled and the pips are added to the die roll to get a total. This total along with any GM or system imposed modifiers is compared against a target difficulty number. To perform an opposed roll action, the two parties involved (usually the player and a gamemaster controlled character) both roll their appropriate skills dice, total them and any modifiers and compare the results. If the first party's roll is higher than that of the second, he wins the contest and the rest of the result is resolved. If the second party equals or exceeds his opponent's roll, then the second party wins the contest.
The Wild Die
One of the dice rolled for each skill or attribute check or for damage is considered to be the "wild die", and is treated somewhat differently from the other dice. This mechanism was added in 2nd Edition. If an initial six is rolled on the wild die, then the die "explodes", meaning you add the six to the total plus re-roll the wild die, adding the result to the total. You get to keep rolling as long as you get sixes. If an initial one is rolled on the wild die, you disregard both it and the highest regular die from the total, often making you fail. Then you re-roll the wild die. If it comes up another one, a critical failure or complication occurs, usually with bad results for the character. Use of the wild die tends to make the game feel more cinematic.
In order to increase their characters' effectiveness, players may spend character points and fate points. The exact number of character points that may be spent is limited by the amount possessed by the character, and the situation that they are used in, with two being the typical limit. Each character point spent adds an extra wild die to one skill or attribute roll. A roll of one has no negative effect with wild dice generated from character points. Alternately, a character may spend one fate point on an action. Characters have fewer fate points, but the expenditure of them doubles the amount of dice rolled on an action.