Splintered Symmetry's game mechanics are built around a simple yet powerful system. Characters are described by 8 core Aspects which exist on three axes of symmetry: half are physical and the other half are mental, half are aspects of strength and the other half are aspects of finesse, half are active and the other half are reactive (which includes the concept of resilience). So, for example, a character's Brawn is their active physical strength, while a character's Awareness is their reactive mental finesse. The 8 aspects are naturally and intuitively balanced. Combined with an open, classless system this creates meaningful choices in character design. For example, Brawn doesn't just impact your carrying capacity and melee fighting. It also affects your movement speed, making it harder to ignore.
There are 16 skills, which represent broad roles that a character trains in, such as Fighter, Medic, or Diplomat. Most tests that a character makes pair an aspect with a skill, and the pairings are flexible, giving GMs considerable freedom in the kinds of tests that they call for. Where most systems use the same perception or notice test for everything, Splintered Symmetry adds a welcome nuance to each situation: you might use a Burglar's Awareness test to catch someone trying to sneak past you, an Engineer's Awareness test to find a construction flaw, or a Mage's Awareness test to notice a faint magical residue.
The dice system is quick and balanced. The standard roll in the game uses three 8 sided dice and picks out just the middle number. This gives a result from 1 to 8, with high and low values being more rare, but without requiring extra addition. Certain game effects can change the roll to pick out the highest number or the lowest. The range of dice results are balanced with the aspect and skill values (which also range from 1 to 8), making for a less luck-heavy system that feels more natural than some other games.
One of the most innovative features of Splintered Symmetry is the boon and curse system. Whenever a character rolls above the difficulty, they earn boons which can be used to purchase additional effects like faster performance, disarming an opponent, or showing off. Players have the opportunity to narrate their successful actions, giving them a more prominent role in the storytelling. Rolling under the difficulty makes a character vulnerable to curses, which the GM uses to purchase additional effects like dropping an item, tripping and falling, or doing something embarrassing. Criticals (a roll of 1 or 8) double the boons or curses, creating memorable moments at the gaming table.
