The loyal, hypothetical reader may recall my wrestling with Critical Hits and Special Maneuvers in Under the Dying Sun. In my last go, I decided that having an event occur on both a roll of box-cars and a roll of 15+ was all just too much and needed to pick one or the other. In the "end" (by which I guess that I mean the end of the post), I chose box-cars as both simpler and more psychologically satisfying. But I was sorry to give up the opportunity for better fighters to have an increased chance of special events. There it stayed for the last few months.
Until I was prowling around on rpg.net, looking at a thread about various ways of using 2d6 in FATE. Marius B suggested in this post that when rolling 2d6 against a positive target number (as opposed to the default FATE method), you had the opportunity to allow special events when rolling doubles that beat the TN.
That was the missing piece. I can keep the simplicity and psychological appeal of box-cars, while still opening up the opportunity for better combatants to increase their chance of a Critical Hit. Since the target number in S&S is a "11", the odds are that only double-sixes will be a hit. But, with a net modifier of +1, you could also get a crit from double-fives; a net modifier of +3 would add double-fours; and so on. You could add the matching piece about fumbles when you miss with doubles, but I have decided not to use that here as it would mean that 99% of folks have a better chance of fumbling than hitting; the lands under the Dying Sun may be harsh, but not that harsh.
As I mentioned in that thread, this is a real head-smack moment for me as I have long admired the way in which Tynes and Stolze's Unknown Armies implemented this idea in a percentile system over a decade ago and blogged about using it not too long ago (while forgetting to credit UA). Sigh.
Anyway, that makes the relevant section in UtDS as follows:
During each of the three Combat Phases (Melee, Missile, and Sorcery), everyone making an attack of that type makes a Combat Roll with varying results:
Roll is snake-eyes: Fumble
Roll is 10- : Miss
Roll is 11+ : Hit
Roll is box-cars or a Hit made with doubles: Critical Hit
If the attacker is using a weapon made of natural, non-metallic materials, it breaks. The Referee should feel free to apply other results; for example, he may rule that Artifacts also break on a fumble or perhaps just run out of power.
The degree of success indicates base damage done. This is modified by the weapon’s Damage Multiplier.
A Critical Hit results in one of two effects: Automatic Hit or Special Maneuver.
Automatic Hit - if the attacker had no chance to roll 11+ due to modifiers (from Weapon vs. AC, opponent's Defense, etc.), he still hits on box-cars. This hit counts as a Combat Roll of "12" i.e. the degree of success is 2. This means that everyone has at least some chance of hitting any foe.
If the attacker has no need for an Automatic Hit, then he can choose a Special Maneuver:
Break Natural Armour/Shield - if the foe’s armour and/or shield if made of natural materials, it breaks and becomes useless. If both armour and shield are susceptible to this effect, the shield will always break first.
Extra Damage - the weapon’s Damage Multiplier increases by one. A Tiny Weapon goes from x ½ to x1, a Small Weapon goes from x1 to x2, and so on.
Wound - the opponent must roll on the Wounds Table (which usually happens only if reduced to 0 or less HP). This Wound is always temporary.
Knock Down/Back - the foe stumbles back a few feet or falls down. He needs to use a Half-Move to stand up or lose all Defense.
Disarm - the foe’s weapon goes flying out of his hand. He must use a Half-Move to draw another weapon.
Stunning Flurry - a flurry of disorienting blows that forces the foe to make an INT Throw or lose his next turn.
Deadly Display - the character's display of martial prowess is so intimidating that the foe must immediately make a Morale Throw. This is only useful against NPC's as player characters never make Morale Throws.