I've always loved the conceit that combat in TTRPGs is "abstract". I've played numerous games that claim this conceit, but then still separate "attack" from "defense" in combat ... as if these are discreet activities. This doesn't feel abstract to me at all -- if feels like a slapfight.

I also love the conceit that combat is "happening simultaneously". But again, all the games I've played that boast this conceit also use turn-based combat, where every person acts serially. This doesn't feel simultaneous -- or kinetic -- to me at all.

My experience is limited, so I assume there are other games out there that do something similar -- and maybe better -- but to address these issues I developed a combat system in house, called the Simultaneous Mass Opposed Roll (SMOR).

It works like this (per the rulebook):

Quote from: Planet Epsilon1. Declare Your Action. Every Adventurer declares what Action their character will attempt to do that Round. The Arbiter will determine your enemy's Action first, but will declare it last.

 2. Everyone Rolls. All combatants roll for their declared Action simultaneously. Actions are resolved in order of the results, from highest to lowest.

An Action is successful if you roll higher than your intended Target.

If a successful Action deals Harm, the amount of Harm is equal to the difference between the two rolls, plus the attacker's Weapon Bonus, minus the defender's Defense Bonus.

In the case of a tie, the Arbiter rolls another die: if the result is even, both Actions fail; if the result is odd, both Actions succeed. If a combatant suffers Harm from a tie, the amount is 2 points.

In some cases, an earlier Action will negate a later Action, such as when the slower combatant is slain or otherwise incapacitated by the quicker attack.

Quick translation guide, in case it's not obvious:
Adventurer = PC
Arbiter = DM
Harm = Damage
Defense = Armor

The single roll determines initiative, to-hit, and damage, for all combatants at once. We've been using this system for 2.5 years now, and it has been truly awesome. Lightning fast and very exciting combat.

Note this is not a straight drop-in replacement for OSR games by any means. I discovered the bumpy way that a lot of widgets depend on there being turn-based space between combat events.

And it took getting used to the pace, which almost seemed too fast at first. In particular, there is no space for reactions within a round -- in this system, your reaction is your next round's action.

Thanks for posting this! I'm definitely going to be giving this approach some thought for my own games. If any questions come up I'll post them.

Quote from: Nakana on March 18, 2025, 06:25:31 PMThanks for posting this! I'm definitely going to be giving this approach some thought for my own games. If any questions come up I'll post them.

Cool, I'd love to hear what you come with as well, I'm always looking to improve.