This is the Duel Engine, a simple RPG combat engine. This basic version of the engine pits a ninja against a samurai, and is functionally complete as a DM tool. The instructions are in-game, and the rules are presented below; don't worry, it's nowhere near as complicated as it seems. Please let me know what y'all think. Thanks in advance!
Rules: Players take turns attacking, and defend against attacks automatically. Each player has twenty points of stamina. When attacked, players consume stamina by defending themselves; the amount of stamina consumed depends on the attack. When a player's stamina is depleted, the player collapses from exhaustion and loses the match. Each turn grants the player one action point; it is possible to accrue additional action points and use them on a single turn. The methods for doing so, as well as the actions they can be spent on, are in-game.
For those wondering about the logic behind attack damage, the formula is:
Sum Of Attack Damage * Sum Of Attacks
So a 1/2 combo would deal 1+2 damage * 2 attacks for a total of 6, whereas a 1/1/1 combo would deal 1+1+1 damage * 3 attacks for a total of 9, and so on. Generally, the more attacks you use, the more stamina damage you'll deal against your opponent. The more costly attacks have effects to make up for the lower stamina damage per action point.
Please note that there are two minor issues with failing to stagger an opponent (more on that below). If, upon performing a Double attack, the opponent's action points do not reduce by one, and instead, something briefly flashes above the opponent's portrait, this signifies that your attack failed to stagger the opponent. In case of a Double/Double combo, it is possible to see both occur, if one stagger connects and the other does not. This is a minor interface issue that does not affect the functionality of the engine, and will be remedied soon.
Edit: updated the engine to include most of the instructions/explanations in-game. This should make it a lot more accessible. Please let me know if it helps.