Analyzing Tabletop RPG Combat Systems, Part II

The Approach of ACKS and Ascendant Explained

Aug 10, 2022

Last week, I presented my analysis of tabletop RPG combat systems, explaining how preferences for maneuver versus attrition and risk versus reward create maxims of design. Now, in Part II of this essay, we’ll show how the contradictions inherent to these maxims frequently yield boring combat, and how game design can circumvent these problems and make combat fun.

As a refresher, here’s a restatement of the maxims:

The more that an RPG exposes its players to risk-laden challenges that lead to improbable successes, the more fun it will be for them.
The more often an RPG causes players to fail when acting, the more frustrated they will be by the system.
The less frequently a player gets to act, the more likely it should be that their action succeeds.
The harsher the consequences of defeat, the more likely it should be that the party’s operations succeed.
The more players that are expected to cooperate in battles, the more attritional the overall combat paradigm should be.

How to Design a Bad Combat System Using the Maxims

Many, perhaps most, RPG combat systems are poorly designed. Hence the adage that a role-playing game offers “a half hour of fun packed into four hours.”

Some RPGs define themselves by character’s mechanical development over a series of encounters, such that at 1st level a player is already planning his “character build".” Such games requires finely-tuned encounters with virtually no likelihood of character defeat, because permanent death ruins the development arc. To achieve this, the designers create combat systems with exceptionally predictable outcomes. Such combat systems are usually called “slogs” and feature combat that is almost entirely attritional. The best example is D&D 4E, which removed all of the battle-winning “save or Die” effects from D&D, flattened damage values, and increased hit point pools.
Some RPGs seek to simulate “realistic” combat, in which every attack can be potentially lethal. They then counterbalance the lethality by making attacks quite unlikely to hit. Such combat systems involve countless rounds of “whiffing” at each other, making players feel like their “heroes” are Benny Hill deputies. A great example is Warhammer FRP 1E, in which a character has a low percentile chance to hit, and even if he hits, can see his attack blocked and rendered moot. GURPS can also be very whiffy under certain conditions.
Some RPGs, designed to be played in large groups of 4-8 players, nevertheless make it highly probable that a character’s turn will be wasted with a failure. Most “whiffy” games have this problem, but any game design that features inaccurate attacks and low damage to hp ratios will qualify.
Some RPGs have very punitive combat systems with high consequences for defeat combined with limited chances for heroic success. These games can appeal to a certain crowd of masochistic simulationists who enjoy plan-or-die scenarios (I am one of them) but rarely become popular among mainstream gamers who want to feel like heroes, not staff officers. Examples here would be Revised RECON, Twilight 2000, and similar mil-sim games.
Some RPGs are designed to promote cooperation between party members with different niches, but then use sub-systems in which half of the niches are attritional and half are maneuver based, preventing cooperation. This criticism could be applied to early versions of D&D, where “save or Die” effects function against creatures regardless of their hit points. Later editions “fixed” this…

It’s important to note that because players have complicated preferences, the maxims themselves can be contradictory. Fixing one problem can lead to another, as happened when 4E eliminated “save or Die” effects so combat would more attritional, but ended up creating a slog. Just as irrigating crops in Mesopotamia resulted in salting the fields so much that they dried out, sometimes the solution to the problem creates a worse problem.

Autarch’s Approach to Designing Tabletop RPG Combat

The approach I take at Autarch to designing tabletop RPG combat relies on categorizing combat into four different cases or classifications. I believe these cases match the intuitive “feel” that players want and expect for different types of match-ups, and lead to combat that meets most of the maxims most of the time.

Case 1. Weak Attacker v. Weak Defender: The mechanics are structured such that the attacker is moderately likely to hit his target (30 - 50% chance). If he does hits, he is very likely to kill his opponent (75%+). This case applies to encounters between, e.g., a 1st level fighter and an orc. The negative effects of “whiffy” and “swingy” combat are tolerable because the character is understood to be unskilled and low level, and is not hard to replace.

Case 2. Weak Attacker vs. Strong Defender: Here, the mechanics are structured such that the attacker is unlikely or very unlikely to hit his target (5% - 25%). If he does hit, he will only attrit his opponent to a limited extent, perhaps 1/10th of his capabilities. Team attack mechanics might increase the chance to hit while reducing the damage. When large numbers of weak attackers assail a strong defender, the laws of probability result in relatively but not entirely predictable outcomes of attrition. This case allows a hero to wade in against a horde of foes with the certainty he can survive for at least a few rounds, while at the same time ensuring that it’s not risk free and over time the hero will be attritted. It also enables numerous weak player characters to team up on a very powerful enemy with some chance of success.

Case 3. Strong Attacker vs. Weak Defender. Now the mechanics are structured such that the attacker is likely or extremely likely to hit his target (66% - 95%). If he hits, he is very likely to kill his opponent. In addition, there is a chance for some special event to occur. The special event is less likely than a single hit, but more useful, thus making the otherwise certain “hit, kill” into something more interesting.

Case 4. Strong Attacker vs. Strong Defender. Here, the mechanics are structured such that the attacker is likely to hit (66% to 75% is ideal), but any hit will only attrit the enemy by about 1/3 to 1/5th of his capabilities. There may still be a chance for a special event, but it’s not necessary.

Thus weak attacker vs weak defender is essentially “pure” maneuver, while strong attacker vs strong defender is essentially “pure attrition. Weak attacker vs strong defender has the low chance to hit of maneuver combat and the low damage of attrition combat, with the large number of combatants making up for the low odds. Strong attack vs weak defender has the high chance to hit of attrition combat and the high damage of maneuver combat, with the chance of special events (like cleave chains, discussed below), keeping the combat interesting.

Applying this Approach: ACKS

Let’s break down this approach in ACKS. ACKS is based on Classic D&D from the BX rules era. BX is a very good system at low level, but as it advances, magic-users being to outstrip fighters. A 1st level fighter in BX gets one attack that deals 1d8 damage. A 14th level fighter in BX gets…one attack that deals 1d8 damage. The magic-user, in the meantime, will have gone from a magic missile dealing 1d4+1 damage to one target to a fireball dealing 14d6 damage in a 20’ radius.

This makes it impossible for the fighters to enjoy any sort of improbable success (violating maxim 1). In fights against hordes of foes, a high-level fighter who hits and doesn’t kill a target has effectively failed to do anything useful (violating maxim 2 and 3). The high-level fighter has much more at stake but not much to show for it (violating maxim 4). And the mechanics afford little opportunity for the fighters and spellcasters to cooperate, because they are playing at such different power levels (violating maxim 5).

The key differences between ACKS and its BX brethren are that in ACKS, (1) fighters gain a bonus to damage as they advance in level, and (2) they automatically get to make an additional attack each time they drop a target, with a maximum number of additional attacks (“cleaves”) equal to their level. These two rule changes make combat in ACKS far more satisfying for players than combat in BX.

The damage bonus assigned to fighters by level helps make sure that weak defenders virtually always die when struck, which in turn triggers the opportunity to cleave. An mid- or high-level ACKS fighter’s success is measured by how many enemies he kills each round. He’ll almost always kill at least 1, and enjoys long-tail probabilities of killing as many as his own level of experience! This fulfills maxim 1 (risk-laden challenges with improbable successes) by allowing incredible cleave-chains against hordes of foes. It fulfills maxims 2 and 3 (the combatant rarely wastes his turn) and maxim 4 (high level combatants, who have more to lose, are exponentially more likely to succeed).

It also address maxim 5, although the manner in which it does so is indirect. In ACKS, the role of spellcasters is usually either (a) pre-battle buffing or (b) setting up cleave chains. In the former role, the spellcasters increase the fighters’ number of attacks, attack bonus, or damage bonus, which has an exponential effect because of the possibility of cleaves. In the latter role, the spellcaster aims to reduce the hit points of medium- and high-HD targets with area of effect spells, which in turn enables the fighters to cleave through the enemy.

For instance, let’s imagine a 6th level fighter with 16 STR and sword +2 and a 6th level mage with fireball encounter eight ogres (AC 4, 4+1 HD, 21hp each).

At the opening of the fight, the mage releases a fireball against the ogres that deals 18hp of damage. Half of the ogres succeed and are injured, with 12hp remaining; half fail and are badly injured, with 3hp remaining. The fighter than attacks. In BX, the 6th level fighter would get one attack against one ogre, hitting on 8+, and dealing 1d8+4 damage. He’d kill one badly injured ogre or have a 12% chance of killing a less injured one. Then his turn would be over.

In ACKS, the 6th level fighter will deal 1d8+7 damage. He’ll still kill a badly injured ogre on any hit, but now he has a 50% chance of killing a less-injured ogre, too. And on any kill, he’ll get to attack again, up to a total of six additional times. The mage’s “softening up” of the target has prepared the fighter for an incredible chain of cleaves.

Because of the fight damager bonus and cleaves, ACKS satisfies all the maxims and results in the four cases working as intended.

Applying this Approach: Ascendant

The superhero genre is, in my opinion, the most challenging genre to design. As such I consider Ascendant to be my magnum opus. Unlike ACKS, where I started with a working chassis, Ascendant was designed from the bottom up on a new mathematical foundation. With no obligation to be backwards compatible with retro games, and a blank slate for development, I was able to directly apply my maxims of design and my four-category approach. It is the only purely logarithmic combat system in existence. (DC Heroes/MEGS is only pseudo-logarithmic.) The careful math of Ascendant has the four cases above built-in. No special rules are needed to achieve the outcome; it simply works.

As a super-powered RPG, Ascendant has to handle both physical and psychic combat, which it does by having two sets of combat stats (Valor, Agility, and Might for physical; Insight, Charisma and Resolve for psychic) and two pools of hit points (Health and Determination).

Ascendant is designed so that combat can be totally attritional or totally maneuver focused, depending on your character. Each character has a power limit that defines their total accuracy + damage potential with physical and/or psychic attacks. If you create a character with low Valor/Agility and high Might, then you’ll rarely hit but when you do, you’ll one-shot the foe. If you create a character with high Valor/Agility and low Might, you’ll frequently hit and slowly attrit the foe.

You can dynamically adjust your odds using Combat Maneuvers. The masterstroke of Ascendant is that the expected results of combat remain the same for all optimized combinations at a given power limit. Therefore the choice of how to fight depends on preference and context.

For instance, if you are a high-health slugger in a one-on-one battle with a regenerating foe, you might choose to Power Attack, accepting “swingy” chances to hit in exchange for the ability to one-shot your foe. That prevents you from trying to attrit a regenerating target. If you’re fighting with a group of friends against a nimble, tough supervillain, you might choose to do Fast Attacks that are more likely to hit so that you gradually attrit the bad guy.

The game also allows you to team attack with other party members to improve the chances of hitting and damaging foes that otherwise might be impossible to hit or harm; and it permits you to multi-attack many enemies at once, enabling powerful heroes to wipe out hordes of foes with one attack.

These combat options serve as dials for the player that let you control your attrition, maneuver, risk, and reward levels to your preference.

Ascendant adds to the player’s control over combat by using Hero Points as an in-game currency (representing “zero-point energy” used by superhumans). By spending Hero Points, you can increase your chance of success, decrease the enemy’s chance of success, reduce your damage taken, and break out of onerous conditions. Because of their utility, Hero Points therefore serve as an attritional pool that is orthogonal to your Health and Determination. That is, you can win a fight directly, by depleting your enemy’s Health or Determination, or indirectly, by depleting their Hero Points. This is a key mechanic with several important implications:

Hero Point expenditure enables you to adjust the odds of combat based on your character and preference. A highly aggressive player can make “swingy” hard-hitting attacks, bumping up his chances to hit with Hero Points. A more cautious player can ensure himself of near-certain accuracy with Hero Points. A defensively-minded player can spend Hero Points to reduce his chances of being hit, or reduce damage taken. Risk and reward are in the player’s hands.
Hero Point attrition serves as a bridge between Health and Determination damage types. Normally, a hero who physically attacks deals Health damage while a hero who mentally attacks deals Determination damage. Since these are separate pools of hit points, this would ordinarily prevent the two from playing cooperatively. However, both types of attacks can be resisted and minimized by defensive expenditure of Hero Points, and depleting enemy Hero Points itself advances your odds of winning.
Hero Points also make “save or Die” effects possible without breaking the game or eliminating opportunities for cooperation. A target that faces an emotion adjustment or mind control or blinding knows it may lose the whole fight if it suffers the effect, which encourages heavy Hero Point expenditure to minimize, reduce, or eliminate the risk. That, in turn, attrits Hero Points, making the target more vulnerable to conventional attacks.

Finally, Ascendant has special effects that are triggered by attacks about 8-15% of the time. These special effects can range from psychic disruption that penalizes a target’s initiative and action economy, to knock back that sends them flying hundreds or thousands of yards away, to disintegration that annihilates their atomic structure.

Reviewing our maxims, Ascendant meets maxim #1 with its Hero Points and special effects. Hero Points let players take risks that otherwise would be suicidal, knowing they can attrit their HP rather than Health and Determination, while special effects allow for improbable and awesome victories. It meets maxims #2 and #3 by allowing players to “dial” their play between attrition and maneuver as desired and spend Hero Points to control their odds. It meets maxim #4 by careful math that guarantees that powerful heroes with a lot to lose can do amazing things. Finally, it meets maxim #5 by making Hero Points a meta-attritional hit point that lets all types of attacks function as attrition.

A Special Offer: Axioms Issue 14 for $2.50!

Today I released Axioms Issue 14 on DriveThruRPG. Axioms is Autarch's quarterly supplement for the Adventurer Conqueror King System. Each issue of Axioms offers a mix of short content updates for ACKS, such as new classes, new sub-mechanical systems, explorations of specific themes within the game, short adventure scenarios, and more.

In this issue, Codex and Scroll, we offer detailed mechanics for books. Has anything played a more important role in the rise and fall of civilizations than books? Mechanics cover:

Characteristics of books - format, language, topic, scope, complexity, length, reading time
Reading books, referencing books, learning proficiencies from books
Writing, copying, translating, and producing books
Appraising and valuing books
Creating and using esoteric books with secret knowledge
Creating and using authoritative books that are never wrong
Creating and using collections and libraries of books
Random book generation tables

While designed for use with ACKS, content in Axioms is compatible with any d20-based fantasy RPG built on the OGL. Axioms is made possible through the support of our patrons, who receive early access to the articles on a month-by-month basis. If you're already a patron, thanks for your support!

Click on the image below to buy Axioms Issue 14 for just $2.50.

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