Critical hits done fast and easy
Since the introduction of the OD&D combat system, probably hundreds of critical hit systems have been introduced. These modifications run the gamut from simply applying extra damage to detailing graphic breaks and sprains, internal bleeding, and the horrible squish of important body parts. Most importantly, though, it’s necessary for any successful critical hit system to be playable – after all, if it’s a pain to use, it won’t matter how cool it is.
With that in mind, here’s a critical hit system that works closely with the existing OD&D rules. The result is a system that makes combat more realistic without unbalancing the game or sacrificing playability. For an in-depth discussion on critical hit systems, please see this author’s article of the same name in OD&DITIES #11.
Critical Hit System
This critical hit system is more accurately a critical damage system that reflects the additional hit point loss suffered by the recipient of an extremely well-placed blow. Every attack is a potential critical hit; the determining factor is the result of the attacker’s “to-hit” roll.
For every five points of the modified attack roll greater than the minimum “to-hit” number, the attacker may roll an extra die of damage. Round any fractions down before rolling extra damage dice. Additional damage dice are not modified by ability scores, enchantment, weapon mastery level, or combat conditions. A single damage die is equal to whatever is rolled to determine basic attack damage. For example, a normal sword does 1–8 points of damage, so an extra damage die is equal to 1d8. At higher mastery levels, sword damage is 2–16, so if the attacker is appropriately skilled (Expert Mastery), he may roll 2d8 as an extra damage die.
Critical damage is applied immediately. Challenging (read: evil) DMs may “raise the ante” by allowing an extra damage die for every four points between the modified attack roll and the minimum “to-hit” number. As a final note, be aware that this system works with the official OD&D rules as well as the revised armour class and THMod guidelines.
For example, assume a fighter fires a long bow at an orc (AC 14). Circumstances dictate the fighter’s long bow THMod is +3 and that an arrow’s damage die is 1d8. The fighter’s first “to-hit” roll is 7. Adding 3 grants a total of 10, which is insufficient to hit the orc, who fires back and misses. Next round, the fighter shoots with a 18. Adding 3 grants a 21, which is 7 points greater than the 14 he needed – extra damage dice are indicated. To determine how many extra dice, the PC divides 7 by 5 and, rounding down, gets an answer of 1, meaning that 1 additional damage die is rolled. Thus, the shot causes 2d8 points of damage. If the fighter’s “to-hit” result had been, for example, 24, the total damage dice would be 3d8 [24 – 14 = 10 / 5 = 2 additional damage die].
Critical Hits and Offensive Spells
At the DM’s option, critical hits may be used for offensive spells. However, since most such spells do not offically require a “to-hit” roll, this option should be exercised only if our modified spell-casting system is used in the campaign. If this is the case, critical damage is determined as above, though for the purposes of spell damage, a single damage die is equal to an extra roll of the type of die used to determine damage (not the initial number of dice rolled).1 For example, a fireball inflicts 1d6 points of damage per level of the caster. Assume a 6th-level magic-user casts the spell and, using our system, makes a casting roll of five greater than what he needed to loose the fireball. As a result, the spell’s damage, normally 6d6, becomes 7d6. If the casting roll had resulted in 10 points greater than required, the damage would be 8d6.
1. Allowing critical damage for offensive spells should be carefully considered before play begins. While it is certainly apt to be attractive to low-level spell-casters, it can very easily prove unbalancing at higher levels of play. If this optional rule is used, well and good, but the DM must realise that once it’s introduced into the campaign, it would be unfair to “revoke” it later on.