As I mentioned, I'm using +Chris McDowall's excellent Into the Odd rules for Prison Island NY-1. The biggest change I needed to make was a new starting package chart, which you can see in the original post. I'm also using these house rules:
アドバンテージ/欠点 ADVANTAGE/DISADVANTAGELifted straight from D&D 5e.
損傷 INJURYThe damage and death rules still work almost the same, but every time you take Critical (Strength) damage you also roll on the following chart. I'm considering expanding it to something more like my D&D chart.
Lose a leg.
Lose an arm.
Lose a hand.
Lose d4 fingers.
Lose an eye.
Internal bleeding. Unable to move until healed.
Scar or burn.
Flesh wound. Looks worse than it is.
弾薬 AMMUNITIONIn the spirit of streamlining things as much as possible, Into the Odd doesn't track ammunition. This makes sense in the context of the original game, where players lead relatively well-equipped expeditions from a big, functioning city. It's fine to assume you brought enough ammo. But this setting is about scavenging whatever you can find in a city-prison cut off from the rest of the world, so yeah my players are counting bullets.
素手による戦闘 UNARMED COMBATMost unarmed attacks still do d4 damage as normal, but characters trained in martial arts do d6 damage as indicated on the starting package chart.
交す DODGEThis game grew out of an ill-advised attempt at playing the TMNT RPG. Even after I managed to boil most of the game down to a 10-page document, I still scared my players away. I love it but it's a goddamn mess. This is my one tiny nod to it:
You can skip your next turn to try to dodge an attack against you. Roll a d20 and try to get between the attack's damage and your Dex score.
メカ戦 MECH COMBATHaven't finalized this yet, but I'm considering a hit chart like this:
|2||power cell||5||shuts down|
|3||weapon arm||7||can't fire weapon|
|10||melee arm||7||can't melee attack|
|12||sensor array||5||blind, erratic|
Instead of HP, any hit that does damage would disable that part. Disabling the core makes the whole thing explode, but you'd need a direct hit with something on the order of a rocket launcher (d12). Taking out the power cell or sensor array would also put the mech out of action, and while they're less armored, they're also small and harder to hit.
So for a normal attack, you'd roll on the hit location chart. You could also target a specific part of the mech and attack with disadvantage. Spending an entire turn to aim before attacking would overcome this disadvantage, as would other situational benefits like luring the mech into a vulnerable position, etc.