Success Level - If an action is successful, the roll for success minus the highest roll against it is the action's "success level." Actions with a success level of one or more are fully successful, and actions with a success level of 0 or ½ are half successful.
Difficulty - Difficulty is the total bonus against the success of an action. An action with a difficulty of 0 is slightly difficult, an action with a difficulty of 5 is very difficult, and an action with a difficulty of 10 is nearly impossible. Environment and hastiness can effect the difficulty of an action.
Single Action - When rolling for the success of an action not directed at another character, roll one die for success and one for failure. Add whatever bonuses apply to the situation to the rolls. If the success roll is higher than the failure roll by a full success level, then the action is successful. If the action is successful by 0 or ½ of a success level, then the action is half successful.
Opposing Actions - If rolling for the success of two players' opposing actions, roll one die for the success of each action and add the bonusses. The action with the higher total succeeds and the other action fails, if it is successful by a full success level. If the rolls are exactly equal, both actions are half successful (depending on the situation, this may mean both actions fail.) If an action succeeds by only a half success level, then the action is half successful and the other action fails.
Multiple Opposing Actions - If two or more characters are trying to stop another character's action there can be multiple rolls against the success of that action. If any of those rolls are higher than the one action they are all trying to stop by a full success level or more, they intefere with the action they were trying to stop. If any of those rolls are higher than the one action they are all trying to stop by a 0 or ½ of a success level, then they only partially (½ effect) intefere with the action they were trying to stop.