Some Critical Analysis
When the Die is Cast
Critical hits are really cool. They also traditionally have many issues — player-monster asymmetries, slowing the game down, making mooks more dangerous than thye ought be, etc. I played without them for a while, but my players wanted to add them in, so I’ve experimented with a few variations.
The critical hit rules in the ACKS Heroic Fantasy Handbook and slightly updated in the Judges Journal are pretty cool. If you roll a natural 20 to hit or beat the target’s AC by 10, you score a crit (published a year before Pathfinder 2e used the same mechanic!) for double damage dice, and the target saves vs Paralysis or suffers a random effect from a table (special maneuvers, damaged gear, etc.). I like how this makes marginal bonuses to hit past a net 2+ attack throw valuable (there’s still a hard floor at a net -8+ attack throw, but that’s rather harder to get!).
We tried this for a while, and it played well early on, but when they’d periodically end up fighting high HD enemies, this had the consequence that they would crit many attacks — against mages and thieves in particular, they’d crit most of the time! And monsters benefit far more from those crits than PCs do, because they tend to have multi-die attacks and higher single attack damage in general, making their crits absolutely brutal.
As the campaign climbed to higher levels and attack throws outpaced AC, this only became more pronounced. Fighters and monsters both, when facing weak enemies, might well crit on any hit at all! And when that forces a save vs table lookup, that slows things down considerably; it also is steeply punishing to the d4 HD classes in light or no armor, who now are not only hit more and have less hp, but end up taking more damage.
Taken together, this prompted revision. The first thing we did was to remove the table lookups from “normal” crits, i.e. those scored by beating the target’s AC by 10 rather than an attack of a natural 20. A table lookup now and then is fine, and the chance offers good fun, but limiting it only to natural 20 attack throws helped mitigate that somewhat. We also experimented with crits adding a single die to the attack, rather than doubling the total dice, so that monsters wouldn’t benefit so disproportionately (this same change was made to Backstab in II, which likewise makes it much more suitable for possession by monsters).
This helped, but now it was more obviously emphasized that a given character suffered the most crits simply be facing the most attacks — two high level fighters would only be dealing special critical effects on the rare natural 20 attack throw, but drop one of them on the battlefield and a common soldier will do so to him every round. This seemed similarly unsatisfactory.
The correction we applied on that ground was that, if a natural 20 was required to hit a target, the “auto-hit” effect of a natural 20 replaced the critical effect. This was good and fitting, but still led to poor results versus bugbears (with their slightly better attack throws) or giant tentacle monsters (because they just have a bunch of attacks).
As ACKS II really came together, I also was increasingly seeing a set of monsters that had inherent critical effects, e.g. a giant hyena with a bone-breaking bite triggered on a natural 20 attack throw. This was my inspiration to consider attaching special crit effects to magic weapons, which itself went through a few variations before reaching the conclusion my table has pretty much settled on:
Each magic weapon (and some monster attacks) has a critical effect that occurs when used to make an attack throw that beats the target’s AC by 10 or is a natural 20. (Normally, this either adds one die of damage, or maximizes the first die.)
Some magic weapons (and some monster attacks) also have special critical effects that occur on an attack throw of a natural 20. (E.g. a Vorpal Sword or a bone-breaking bite.)
Characters with Weapon Focus who are wielding a magic weapon only have to beat the target’s AC by 7, rather than 10, to trigger a critical effect. This is in lieu of the normal effects of Weapon Focus.
I share this now because this has been a stable rule that has been reasonably well playtested at this point, and which has largely solved my numerous issues with the many varieties of critical hits. Limiting crits to magic weapons and specific monsters avoids the problems of mooks endlessly critting heroes. Only applying special crit effects on a natural 20 keeps them special and avoids slowing things down. Tying special crit effects to specific magic weapons preserves variety without requiring rolls on a table (or if desired, it ties the table to that weapon and puts the responsibility clearly on the player to keep things snappy).
As an incidental benefit, it also emphasizes the difference between a masterwork +h/d weapon (which doesn’t qualify for crits) and a proper magic weapon +1 (which does), a good emphasis in my opinion to balance the availability of masterworks. It also adds the opportunity for minor differentiation of different magic weapons, which I appreciate.
On the whole, I think ACKS plays fine — better than fine — without crits. But players enjoy them, even if they’re the ones who tend to suffer most because of them, and the potential for a critical hit does lend a certain aesthetic to the gameplay experience. I think the rule above does a good job of capitalizing on those upsides while mitigating the downsides, but as ever, I’m quite interested in hearing feedback from a broader scope!