Anyway, since a big part of beating a four-color superhero RPG into such an unaccustomed shape as this would be just removing material, there's actually good reason not to have the M&M core book on the table at all during play. So this abomination is free to be its own creature, allowing me to make some changes that are more for taste than to fit the specific themes of Dark. The first thing I'd start with would be a minor change to the standard, D&D-inherited ability scores. I'll rename Dexterity and Constitution to Agility and Endurance, and reorganize Wisdom and Charisma into Perception and Willpower. Perception obviously takes over all sensory abilities, but also Initiative checks, while Willpower handles both mental stability and focus, and social abilities.
Oh, and I'd ditch the ability scores and use modifiers alone (True 20-style). That should just be standard practice.
I'll also get rid of a few skills, introduce a few others from the Mastermind's Manual or elsewhere, and reshuffle some ability score dependencies as seems logical. The result (at the moment) is this:
Jump (separated from Acrobatics)
Acrobatics (loses its jump function)
Sleight of Hand
Stamina (similar to D&D 4e's Endurance skill)
Chemistry (effectively Craft: Chemicals and Knowledge: Chemistry)
Demolition (from Mastermind's Manual)
Gunsmithing (effectively Craft: Guns)
Knowledge (might divide this into a few specic skills, like Biology, Tactics, etc.)
Repair (from Mastermind's Manual)
Trapmaking (effectively Craft: Traps)
(Might be a lot of other Craft skills I could adapt...)
Track (the tracking function from Survival, which otherwise doesn't have much use in this game)
I've added a few skills here, but I've subtracted a lot more. Since this version of M&M is intended to run a very specific kind of game, things like Disguise and Ride just didn't seem useful. A PC who plays the harmonica can just be admitted as a good harmonica player, with no need for a Perform skill.
The other big area I'm changing is saving throws: They can go turn into D&D 4e-style "defenses" quite nicely. I'd also add a passive Perception-based defense--also quite 4e-style--called Alertness. This replaces the Notice skill completely. So we'd have the following defenses:
Reflexes = 10 + Agility + bonus (costs 1 power point per +1)
Fortitude = 10 + Endurance + bonus (costs 1 power point per +1)
Alertness = 10 + Perception + bonus (costs 1 power point per +1)
Resolve = 10 + Willpower + bonus (costs 1 power point per +1)
Toughness = 5 + Endurance (These ain't superhuman characters, so they can't increase their Toughness with experience. They have to find some armor.)
(Thinking on my feet, here: What if I moved Toughness over to Strength--since it represents sheer beefiness more than Endurance does, and melee damage bonuses don't count much in a gun-focused game--and then made a lie-detecting Insight defense based on Intelligence, replacing the Sense Motive skill? One defense for each ability appeals to my sense of symmetry . . . although I don't believe that kind of symmetry is a worthwhile goal in game design. Might go with it, though.)
Now people get to make damage rolls! Damage rolls are fun. And instead of comparing a Toughness save result to a damage DC and then calculating the difference to determine the result, every character can have a series of clear and simple damage thresholds right there on the sheet. So if a character's Toughness is 7, it'll say right there on the sheet that a damage roll of less than 7 has no effect, a roll of 7 to 11 produces an injury, 12 to 16 injures and also stuns, 17 to 21 stuns, staggers, and disables, 22-26 leaves the character unconscious and dying, and 27 or more kills the character outright . . . and messily (because a game like this obviously needs a "gibbed" result).
I'm not even going to address non-lethal damage, here, as there isn't really a place for such a thing in this variant.
I'm also thinking about removing the possibility of a "no effect" result (since any successful attack roll ought to hurt the target at least a little), but I'm not sure of the balance implications there. Obviously, this game should be grittier than standard Mutants & Masterminds, but I don't want to go too far.
Anyway, just to keep the damage threshold on each character sheet simple and static, modifiers from a target's injuries and armor would be applied to the attacker's the damage roll instead of the target's toughness score. So when an attack roll succeeds, the attacker rolls damage, adds the target's injuries and subtracts the target's armor value, then compares the result to the damage threshold track on the target's character sheet. I think this would result in faster combat, but I'd have to try it to be sure. One thing I'd like to do to speed things up is keep track of injuries with tokens (poker chips or similar), to that damage bonuses against injured targets can be tracked without resorting to pencil and paper.
I'd also treat Attack and Defense bonuses (maybe I need a different name for Defense, since I turned the Saving Throws into passive "defenses"...) a little bit differently. It's the easiest thing in the world to split Attack into Melee Attack and Ranged Attack. I think, though, that I'd actually have characters pay 2 power points for each point of Ranged bonus, and only 1 for each point of Melee, since ranged weapons will be significantly powerful and plentiful than melee ones. Meanwhile, I can take Defense and the Dodge Focus feat and reverse engineer them into Active Defense and Reflexive Defense: The former costs 1 point per point and is lost when the character is surprised or flat-footed, while the latter costs 2 points per point, can't exceed half of the Active Defense bonus, and works as long as the character can move freely. Strange as it sounds, the costs work out the same as standard M&M Defense and Dodge Focus.
One last thing: I believe I'd use 2d10 for the standard die roll in this system, rather than 1d20. I think a probability curve that's actually curved--and thus produces slightly more predictable successes and failures--would fit gritty, cautious, strategic gameplay a lot better than the flat probability curve of a d20 roll.
Okay, that's way more than enough for now. I'll probably have more to say later, though. I've been thinking about it enough.