Just wanted to get some input on a new game system I'm slowly fleshing out.
Basically, I've been pondering a percentile-based RPG system that requires only ten-sided dice to be played, though a calculator will be necessary as well. I actually like the calculator as a game tool, as most RPGs don't rely on calculators, and the system I've been thinking of could make use of one with out getting too complicated in the calculations.
The system I've been working on is tentatively titled the Universal Percentile System, or UPS. Rather than having percentile-based statistics, it will instead have non-percentile statistics. The percentiles will come into play when statistics are compared to each other as ratios. These ratios will determine chance of success or failure.
Perhaps it'd be better if I talked in specifics rather than in general terms. Here's what I have so far for the Universal Percentile System:
Characters have four basic statistics: Adroitness, Might, Intelligence, and Will. Two ten-sided dice are rolled and added together to determine each basic statistic when the character is created. Adroitness is physical quickness, Might is physical strength, Intelligence is mental quickness, and Will is mental strength.
Once the four basic statistics are determined, the three secondary statistics are determined. The three secondary statistics are Physical, Spiritual, and Viability. Physical is determined by adding Adroitness and Might together. Spiritual is determined by adding Intelligence and Will together. Viability is determined by adding Physical and Spiritual, then dividing the result by two (round up).
Once these statistics are determined they are used to decide all gameplay. The chance of an action succeeding or failing depends upon the statistic of a character matched against an opposing number, which will either be a difficulty number determined by the GM or will be the statistic of an opposing character/creature. The formula used to calculate success is as follows: Add the character's statistic to the opposing number, then divide the character's statistic by the total to get the percentage chance of success. Mathematically, this can be expressed as (Character's statistic) divided by (Character's statistic + opposing number). This of course is where the calculator comes in, as the result of the division must be converted into a percentage chance.
For example, let's suppose a character is fighting hand-to-hand with another character. When determining if a strike hits, the statistic used by the attacking character will be Physical, and the opposing number will be the defending character's Physical. Suppose both characters are evenly matched with Physicals of 15. The chance for the attacking character to hit is 15 divided by 30 (which is 15 + 15), which equates to .50 or 50%. This means that two equally matched individuals have a 50/50 chance of hitting each other in combat... makes sense to me, or at least gives me some basis to say the ratio/percentile system I'm working on has some logic to it worthy of a realistic game system.
As far as damage goes in combat, weapons will do a certain amount of damage that is then compared to the target's Viability to determine a percentile chance of wounding the target. For instance, a weapon that does 10 damage to a character with Viability of 20 has a 33% chance of wounding (10 divided by 30, using the ratio determining equation for conflict resolution). If a wound roll succeeds, the target gains a wound factor. For each 10% a wound roll succeeds by, an extra wound factor is gained. I haven't fleshed it out yet, but wound factors will cumulatively harm a character/creature worse and worse the higher the wound factors go, until death occurs, of course.
So, I have a basic system for combat using the above rules. Spiritual combat can occur as well, only using the Spiritual in place of Physical. Non-combat conflicts will occur using the same way of determining percentile chance of success ratiowise. I'm thinking skills will be learned by characters and come in two varieties: Physical and Spiritual. For every 2 Physical a character starts with, they learn 1 Physical skill. For every 2 Spiritual a character starts with, they learn 1 Spiritual skill. Physical skills include weapon use and any skill that relies on the physical. Spiritual skills include spells and any skill that relies on the mental. A character may use their full statistic when using a skill they have. Otherwise, the appropriate statistic will be divided in half or reduced to zero if the character is attempting a skill they do not know. Basically, if something is common, anybody can do it at full statistic... if something is uncommon, anybody can attempt it at half statistic... if something is rare, it cannot be attempted, as the statistic is reduced to zero for the unskilled.
So, there's a basic outline of the Universal Percentile System. Any feedback?