I picked up Rotworld a few months ago. It uses the "Action Table" system from the old Pacesetter games like Chill and Timemaster. In this system, there's an ability score (1 to 100) and a defense class (1-10), and the player rolls a percentile die to get a result, which is one of: S, L, M, H, C, modified by a possible K.
The way that these things go together does not seem to be predictable or systematic, nor do the meaning of S, L, M, H, or C. I like Rotworld as a set of ideas, but this system seems impossible for me to internalize. I am tempted to just use a different system for the setting.
Is there a trick to learning this system so that I won't be constantly looking at this table and the skill result tables? Is there a commonly-used simplification that can be memorized, if the action table can't? How does this system get used in actual play?