Ordalia is a customizable game system based on collectible playing cards, that mainly simulates a fight between two or more players. The basic mechanics is "turn based", and consists in both players choosing a card maneuver (each card simulates an attack, a defense or another type of movement during combat) and optionally an event card (which simulates the use of special skills, random events or other techniques) each turn.

When all players have made their choices the game compares the selected cards and, according to the characteristics of each playing character, determines the outcome of the combat round (missed, hit, wounded, and more).

While the general mechanics of the game stay the same, the game itself can be contextualized in many different settings and backgrounds (even different from combat), each one with its own specific cards and character types.