I was working on my rogue-like and an idea for a sort of combat system struck me. Initially I'd thought of it as a computer game of some sort, but the more I think about it, the more I think it could probably be done as part of a PnP RPG, with enough tokens and such. My first thoughts were for 1v1 combat, although it could probably be modified to have more combatants pretty easily.
I picture it in a medieval setting, and while it could be modified for another setting, it wouldn't likely work so well with ranged weapons.
Combat would be turn based. Each character has a number of actions they can perform, each of which takes a number of turns. For example, a character could swing their sword in a wide arc, or perform a quick jab. The swing would take more turns, and the character wouldn't be able to take other actions during that time (although it would likely do more damage if it connected). Each character would be given a chance to choose an action at the beginning of the game, and again each time their previous action ended.
Some actions might allow the character to choose the number of turns they spend performing it (waiting or blocking for example), but they wouldn't be able to interrupt them once they've started. Each character would be able to tell what the other was doing (or appearing to do, if the characters can feign attacks) and when it will finish.
Each character would need only two stats, health and stamina. Actions would use up stamina, which would regenerate at a steady rate. A healthy character would recover stamina faster than a wounded one, and characters with low stamina would take longer to perform actions (with the exception of things like waiting and blocking...). This would allow a player to wear out a wounded opponent, slowing them enough to keep them from blocking the more powerful attacks. If the system were used in an RPG setting, weapons could alter damage and attack speed (a dagger would swing faster, but wouldn't cut as deep).
Actions would include a decent number of strikes (one for each direction, maybe two in some cases, to allow a slow attack and a fast attack), the ability to feign any of the previous strikes, the ability to hold a block in a given direction (would stop most/all damage, but the character might recoil or be stunned for a moment), the ability to parry in a given direction, which would take a preset number of turns, but if timed right would cause the opponent to recoil/be stunned, and the ability to wait for a number of turns. This obviously isn't a full list, but that's the majority of the actions the characters would need.
Before I invest further time into trying to come up with the numbers and other details, are there any glaring flaws in the concept as it is? Anything I should add/take away? Any other (constructive...) criticism, etc. is welcome, and appreciated.