MOSH's combat is designed to be a highly lethal fail state. Squaring that with a game where players also have magical space kung fu (or combat sleeves) that set them apart from a random NPC with a gun presents some challenges. With sleeves, I've addressed this issue by giving players better tools in the fail state in exchange for risking permanent death and a panic death spiral that makes combat harder to avoid.
Space kung fu presents a slightly trickier problem but here's a preliminary set of rules (note that I'm assuming the rules on hits and weapon damage released on the MOSH discord are in play -- players have hits and weapon damage is more constrained:
SOME SIMPLE RULES FOR SPACE KUNG FU:
- Remove all stat bonuses for combat sleeves and the like and let players describe their cybernetic implants however they want. All the players are similarly powerful. In the grand scheme of things they're still nobodies: the background ninjas, axe gang mooks, etc., but relative to a random NPC on the street they're tremendously dangerous. Some NPCs probably warrant reduced hits and stats.
- Give everyone a single extra hit with HP generated as normal (Marines will have 4, everyone else will have 3). Unlike a player's other hits, losing this one has no consequences and doesn't entail a roll on the critical hit table.
- Permit players to defend against ranged attacks with an opposed combat roll and counterattack against any opponent they're aware of and can see. You could view this as a Jedi deflecting blaster bolts but you could also view it as Jackie Chan making creative use of his environment or a combat sleeve's superior reflexes allowing it to shoot someone popping out from behind cover before they get a shot off.
- Abstract weapons and damage a little more; gear really shouldn't matter as much except for certain standout specialist weapons like the smart rifle and combat shotgun or a sword with a legendary pedigree.
- Permit combat maneuvers (2 successful combat rolls)
- All players have a "style" (it needn't be a formal martial art but you should probably name it like one because space kung fu and give a brief description). When performing combat maneuvers consistent with their style, players roll 1 of their 2 combat maneuver rolls at advantage. A player may learn other styles as they would an expert skill
- Adjust narrative permissions to reflect more capable characters; they can jump higher, run faster, do ridiculous parkour, etc.