So that means we need a task resolution mechanic. Let's go with d20+modifiers because reasons. Now we need actual tasks to resolve! We'll call them 'minigames.' We want people to fight and some way of telling who wins. Combat minigame! We want people to talk and lie - not to the GM, so we'll need some way of adjudicating that outside of blowing the GM's cock - social minigame! Also, sneaking is a big part of stuff, so we'll need a stealth minigame. We should probably have something set for how characters move when we care about them moving - during a minigame.
Does that settle it? Probably not, but I feel that's a good starting place. Now, let's figure out at least the basics of what the minigames will look like. Let's start with combat, because it's the one people who aren't me care about more.
So what happens in combat? Someone's gotta hit someone else. They should probably have a chance to miss. This being pulp, people should rarely miss because of a lack of skill - people should miss because of their enemies skill in not getting stabbed/shot/fireball'd. And also, even if they do hit, if they ain't got the chops to actually do damage, their attack should do nothing. (Like Indy trying fisticuffs with some enormous bruiser who just stands there and laughs.)
So we can see we need at least three stats to start with. Some way of telling how good you are hitting your target - let's call that your Attack. Some way of telling how good you are not getting hit - let's call that Dodge, and some way of subtracting damage if an attack does hit - let's call that Armour. (All subject to change, like everything else.)
So since we want people to dodge instead of people missing mostly, we should make Attack and Dodge be opposed rolls. So dude one is slicing at dude two with a sword. He's going to roll a d20+Attack vs d20+Dodge, maybe? But that'll probably mean people are in fact going to missing all the time, which is boring.
Maybe let's make Dodge be a direct modifier to Attack, to represent that it is in fact harder to hit a fucker who's jumping and rolling and weaving. We still need to roll against something, though, so it looks like we'll need another stat - Defense, which we want to be a static number so combat isn't so horribly swingy. Let's say Defense will be based off Dex+Int for no good reason. Will that make Dodge a skill? Maybe, or we might just merge the two. For now, let's pretend Dodge is a skill and Defense is 10+Int mod+Dex mod, representing your general split-second ability to defend yourself. So now we have something that looks like this:
- Attacker rolls d20+attack-target's dodge vs target's Defense
So if dude one is swinging a longsword for 1d8+8 damage against another dude in plate armour (8 Armour), does that mean his attack only does 1d8? Eh, it could, but we can also say that if Attackers Damage Bonus>Defender's Armour, the attack does nothing.
But wait! That means the rogue with no damage mod on his dagger will never be able to do any damage to the dude in plate armour, like say assassinating him cause he's a palace guard and they want to sneak into said palace. That is a great point, so we should probably make some sort of mechanic that allows the rogue to assassinate Palace Guards in plate armour - maybe something we'll call a Called Shot, or Sneak Attack! Maybe some weapons will also ignore X amount of armour, too, we'll see.
Now we've established how someone hits someone else, how that person dodges, defends, and reduces damage, we should have a way to track how much damage someone's taken. We'll use Hit Points! And when someone is reduced to 0 zero hitpoints, they're bleeding out and about to die.
Now let's make up numbers and show an example of this in action.
Farmer Joe is pissed off at Farmer Ben because Farmer Ben slept with Farmer Joe's daughter. Farmer Joe swings his scythe at Farmer Ben. Farmer Joe has used that scythe his entire life, so we'll see he has experience using that scythe, giving him Proficiency. What does Proficiency do? Because we don't people to feel bad about using new weapons, we'll say Proficiency gives you a bonus, and not having Proficiency doesn't give you a bonus, instead of giving you a penalty. Farmer Joe, then, has a +2 bonus to Attack because of his Scythe or Farming Implements Proficiency, in addition to his str of 16 (cause he's a farmer), giving him a +3 str mod. His Attack then, would be +2 (Proficiency) +3 Str = 5. Farmer Ben was a soldier in the Last War who learned how to not get stabbed a bit, so we'll say he's got a dodge of 5. Uh oh, this gives Farmer Joe no bonus to hit!
Let's say Farmer Ben isn't the sharpest tool in the shed (or he would've known that Farmer's Joe's daughter was engaged and may have only been seventeen), so he's got an int of 9. He's quick on his feet, though, so let's say a Dex of 14, giving him a Defense of 10-1+2=11.
Farmer Joe will hit Farmer Ben with the Scythe 45% of the time - which is good for Farmer Ben, though Farmer Ben better hit back or run away, since 45% means he's going to hit Farmer Joe sooner rather than later.
To whit: Attacker rolls 1d20+Attack-Defender's Dodge vs Defender's Defense=10+Int+Dex. On a hit, Attacker deals Weapon Damage if Damage Mod>Defender's Armour. Other no damage.
How's that look? Next up, social minigames!
Some issues I can see: Dodge scaling. Depending on how Dodge will progress, it might well result that Attack is always reduced to 0. Armour - every attack will either need to get a damage bonus from somewhere, or explicitly ignore it. If too many things ignore armour, then armour becomes useless. Defense - if Dodge scales too high, and Defense is too high as well, it'll be a fun missfest. Those are balancing issues, I think, though.