As for Chivalry & Sorcery (and specifically, the 2nd Ed. with the D20 combat system)… well, it’s what made our group decide to adapt lots of its rules to AD&D play. The combat system is actually pretty good, if you resolve and clarify a couple of minor issues. When I first played it, I was surprised to find that it was very smooth going and a lot of fun. It generated plenty of fun results through the interplay of Attacks and Active Defenses, and Criticals an Bashes. For quite a while we played AD&D (character creation and classes, magic system, etc…) with C&S combat rules. Later we started tinkering with the magic system, and adapted some of the C&S rules to the AD&D spells.
In C&S combat characters have a certain number of Blows (actions) they can use, for either attacks (some attacks require the use of 2 Blows) or Active Defenses (Weapon Parry, Shield Parry and Dodge). Defenses come in the form of penalties to the attack. So a certain Parry might apply a -5 to the attackers roll, for example. A successful defense would be if the attack failed because of the Parry (in this case by a margin of 5). A Critical Defense would occur when an attacker rolls a Fumble (a natural 1 in terms of D&D) against a given defense. The interplay of Attacks vs Defenses generate various “events”. A successful Weapon Parry might mean that a weapon breaking roll is required, or might allow the defender to spend one Blow to attempt a disarm; a critical weapon parry would give the defender a Free Blow (attack of opportunity in D&D terms) to attempt a disarm or any other special skills he might have. A successful Shield Parry allows the defender to attempt a Bash by spending a Blow, and a critical gives a Free Blow for that Bash, or for some other Shield Skill. A Dodge allows the defender to spend a Blow and Disengage from range, while a Critical Dodge gives the Defender a Free Blow to either disengage or to counterstrike, etc…
So a lot of tactical events occur which are more fun than the usual monotonous rythm of ad&AD&D1 combat, without making combat a lot more complicated. Each weapon has both a Critical range and a Bash range, and if the roll is within the range, and succeeds by a minimum margin of success, then a Crit allows the attacher to roll extra dmg, typically under the form of one extra die of damage, and a Bash allows the attacker to roll 2d6 on the Bash table, which will generate results such as knocking the opponent back, or to his knees, stunning him or causing him to lose a Blow, etc… taking into account the relative sizes of weapons and combatants, and whether they have armor nos under the form of minus or pluses to the roll.
One of the things I enjoy in this system is that it doesn’t really add a lot more die rolls to the usual combat sequence resolution, only if special results occur. Obviously, our system is quite different than the original C&S2 since it is adapted to AD&D1, more streamlined (the original rules are quite confusing and badly organized) and some ideas of Codex Martialis were added to the rules (the various weapon attack modifiers, combat ranges, etc…).
And I’ll write about C&S magic later, gotta go!