OSR How to Implement Attack Roll to Damage in d20/OSR?

[DammitVictor]

I am currently designing my own contribution to the world of OSR-- Sellswords & Godwars: Old-School Player's Options for Fantasy Roleplaying-- that attempts to model AD&D Player's Option (with ICE and Palladium influences) using the core mechanics of the d20 System.

One nod that I would like to give to the game's ICE heritage is enhancing the damage of a successful attack based on the margin on the attack roll.

The attack roll is pretty solidly defined at this point: you roll d20 and add two ability mods (DEX and another) + your Attack Bonus (from feats) + your Proficiency bonus. Other attack bonuses are possible, but pretty limited.

Right now, I'm thinking that I can replace special combat maneuvers by giving each attack form (weapon/spell) a list of bonus options. You get 1 option for a successful option, and 1 option for every five full points you beat Armor Class. Other options are +X damage per +Y margin, or +1d damage per +Y damage, with Y defaulting to 5.

Have any other d20 games done this well?

 

[Charlaquin]

I am currently designing my own contribution to the world of OSR-- Sellswords & Godwars: Old-School Player's Options for Fantasy Roleplaying-- that attempts to model AD&D Player's Option (with ICE and Palladium influences) using the core mechanics of the d20 System.

One nod that I would like to give to the game's ICE heritage is enhancing the damage of a successful attack based on the margin on the attack roll.

The attack roll is pretty solidly defined at this point: you roll d20 and add two ability mods (DEX and another) + your Attack Bonus (from feats) + your Proficiency bonus. Other attack bonuses are possible, but pretty limited.

Right now, I'm thinking that I can replace special combat maneuvers by giving each attack form (weapon/spell) a list of bonus options. You get 1 option for a successful option, and 1 option for every five full points you beat Armor Class. Other options are +X damage per +Y margin, or +1d damage per +Y damage, with Y defaulting to 5.

Have any other d20 games done this well?

Funny you should mention it, Paizo is currently doing previews of their upcoming Pathfinder Second Edition, which is adopting a similar concept, with four degrees of success - critical failure at 10 or more below the target number, failure at less than 10 below the target number, success at equal to or the target number or greater than it by less than 10, and critical success at 10 or more above the target number. By default, critical success deals double damage on an attack roll, and critical failure doesn’t do anything worse than failure on an attack roll, but there are various maneuvers that will interact with the degrees of success, such as Sure Strike which does damage as if you had rolled the lowest number on all damage dice on a failed attack roll (but still no damage on a critically failed attack roll), or Twin Riposte, which allows a character wielding two weapons to attack an opponent who just critically failed an attack roll against them.

Another game you might want to look into is 13th Age, which as far as I know doesn’t do success thresholds like this, but does include some maneuvers that trigger depending on the result of the attack roll, usually on either an odd result or an even result (and a few abilities allow characters to actually give themselves -1 on an attack roll after seeing the result, effectively allowing you to turn an odd result even or even result odd if it hit by 1 or more above the target number.)

 

[GMMichael]

Have any other d20 games done this well?

Who cares? What does your game do well?

Extra damage on a higher roll is cool, but so are spectacular effects. I wouldn't add more effects with higher results though - I'd just offer cooler effects with higher results.

Check out Dragon (Fantasy?) AGE. The Stunts are similar to what I'm thinking.