A Critical Success is a rare occurrence when a character's action produces the intended result in a spectacularly successful fashion.

When a 6 is rolled for a Dice Check, roll another D6. If another 6 results, the action is considered a Critical Success.

There is a 1/36 (2.78%) chance of a Critical Success for any action, and the degree of the ensuing success can be expected to be inversely proportional to it's likelihood!