General Roll/Check Mechanic
Checks/Rolls are only made for actions with consequences or risk (including damage, wasted time when time is relevant, someone getting away, etc).
There are 4 possible results from a check being made.
On a failure, either you don't accomplish what you're trying to do, or you accomplish it in a disadvantageous way, whichever is more interesting for the situation.
On a success, you accomplish what you're trying to do.
On a harsh failure, you fail in a way that's sure to create complications or twists, or is more punishing than a normal failure.
On a critical success, you get something extra on top of your success, or achieve a more complete success.
Each action described below requires you to roll a certain number of 6-sided dice (usually equal to Skill). When you do so, count the number of dice that are 4, 5, or 6. This number (noted as hits) is compared to either a static number (for a passive difficulty) or an opposed roll's hits (for an actively opposed action). If your hits are greater than that number, the result is a Success; if not, the result is a Failure. If your hits exceed twice that number then the result of the action is a Critical Success.
If at any point you would normally roll zero dice, you may instead roll one die. This die succeeds on a 4, 5, or 6 as normal, but a 1, 2, or 3 counts as a harsh failure instead of a failure.
When making rolls, you choose to what degree you’ll Risk the action. This involves picking a level of risk from 0 to your Risk Limit. Roll your check with extra dice equal to this amount (known as the roll’s Risk). If you do not achieve enough hits to achieve a Success and you roll hits greater than or equal to your level of Risk, your Failure becomes a Harsh Failure.