Long Lists of d100 Combat Modifiers

We were playing a game of the classic Star Frontiers the other day, and George and I noticed what a hassle it was to constantly calculate a character's chance to hit with the combat modifiers chart. Every turn, the modifiers changed due to the situation, movement, range, cover, and a bunch of other factors. Every turn, for each character, it went something like this:

"...range, medium, -20; target is running, -20; firer is stationary, +0; etc."

Granted, the numbers and percentages are such where you can do the math in your head, but the process of adding and subtracting all these numbers dragged the game down. In short, it was quick work, but a lot of rapid-fire math which ended up feeling pretty heavy over time.

This is a common trait of old-school percentile games, the heavy use of percentage based combat modifiers - often in long charts of situational modifiers. Top Secret, Gangbusters, Star Frontiers, Space Opera, Rolemaster, and a bunch of other d100 games all have this in common. Even the 2d6 wargame Car Wars eventually spawned a huge combat modifier list, and the RPG GURPS has an even longer list on modifiers for its 3d6 scale. All these games share the <<please wait, calculating modifiers>> step in combat, and they all have that same innate slowness to them.

Compare and contrast this with AC, and the to-hit charts and systems in AD&D through D&D4. In most of the D&Ds, they account for many of the fiddly modifiers in AC, and it usually falls to the referee to apply a final situational modifier based on the circumstances (some versions do not encourage this). Granted, there are some d20 systems (and even D&D variants) that start adding in modifier charts, but for the most part, you are setting one number once, and then rolling from there. The classic d100 games crept closer to real-life simulation, and thus had to account for all sorts of crazy and specific modifiers.

Many of these games included the caveats to 'let the referee decide the final modifiers' and 'use these charts as guidelines', and you did see later games move away from these specific-case modifiers to a more general system (easy = +0%, medium= -20%, hard = -40%, etc). All this evolved into the referee set DC and AC system you see today in D&D; along with a couple other pool and success based systems we see in Shadowrun, World of Darkness, and a couple other games.

The old iterative percentile modifier charts were hard to use, and slowed the game down - even if they were straightforward and to-the-point, like Star Frontier's charts. Repeated use made them familiar, but there was still a lot of addition and subtraction that makes a straightforward d20 + mod vs. DC roll look simple in comparison. There are other nice dice systems that modify dice or target numbers, which also help keep things simple and fast.