Acting is an ancient and honoured profession. The first plays date
back to Greece in the sixth century BC, in which a single actor
portrayed a scene. The famed dramatist Sophocles shortly expanded
the scope to include three actors. Still, plays were performed
solely be men, suitably costumed for the roles of women. Over two
millenia passed before women were accepted as having a place in
drama, although there are other civilizations in which women were
traditionally the actors.
Naturally, Acting is a useful skill for any character who hopes to make their fortune on stage or the silver screen.
Acting can also be used in conjunction with the Con Artist skill, to provide an additional advantage to characters who have both skills, which makes it useful for a character who intends to engage in deception or trickery. When such a character makes a Con Artist skill check, the GM may rule that his acting ability will be useful. In these cases, the character's skill level in Acting as a percentage of their skill level in Con Artist is an additional modifier to the skill check.
Matt has a skill level of 60 in Acting and a skill level of 54 in Con Artist. If the GM allows the extra bonus in a certain situation, Matt effective skill level before any difficulty ratings or modifiers will be 86(=54+(54*.60)=54*1.60).
Note: The Con Artist skill never affects the Acting skill, only the other way around.
Since characters can't watch themselves perform, the GM rolls all Acting skill checks. If the result is within 25 of the effective skill level (either way), the character is satisfied with the result. If the check passes by more than 25, the character is pleased with the result. If the check fails by more than 25, the character is not pleased with the result. In the case of critical successes and failures, the character will be very pleased (or displeased) with the result.
Matt is trying to play a difficult part, while wearing an inappropriate costume. His skill level in Acting is 60, and the GM assigns a difficulty of 30, leaving Matt with an effective skill level of 30(=60-30). If the GM rolls anywhere from 5(=30-25) to 30 on Matt's skill check, Matt will succeed, but only be informed that he was satisfied. A roll of 31 to 55(=30+25) means that Matt failed, but is still satisfied. Matt will have a better idea of what his performance was like if the roll is outside of this 5 to 55 range.