My favorite RPG as a kid was TSR’s Marvel Super Hero RPG. There are several places where you can get this material for free and it’s all legal. Not sure how that worked out but it’s true. Here’s one place. http://mshgamer.com/downloads/book-resources/

I have tried several different superhero rpg systems and for one reason or the other, none of them have really excited me. I have no doubt that the narrative dice system can handle the story aspects of a superhero rpg. What about scale? Mechanically how do you build Superman? The Flash’s powers? Do you break the cap and let attributes creep up to six? Is Iron Man’s suit a vehicle?

How would you build your favorite superhero?

I’m taking a modified Human Archetype , 2’s in Agility and Presence, 3’s in Brawn and Intellect, 4 in Cunning, 1 in Willpower after spending my starting 100xp. Cunning and Brawn are the super stats. Brawn is now a 4 thanks to my first Dedication. Born to a rich family I have a lot of money, I start every session with another 100 dollars, usually in the form of some cool gadget. After the loss of my parents I have had to learn to lie to hide myself behind an emotional wall, I have a Rank is Deception from the start

For a Career I’m a Vigilante. Brawl, Coercion, Deception, Mechanics, Stealth, Streetwise, Skullduggery, and Vigilance are all career skills. With the help of my Buttler I have added Athletics, Driving, Perception and Ranged Light to that list. Most now sit at 3 ranks, although Brawl, Coercion and Deception are all at 4.

For Talents I have plenty, I’m tough and unrelenting; Grit, Toughened, Durable, Enduring, I’m a Supreme Armour Master... I have them all. Then I have A knack for making an Impossible Fall as I’m also Conditioned , I have a Utility Belt of awesome gadgets, I’m Intimidating and use fear to fight fear, Preying on the Weak. When I drive it’s usually Offensive, breaking everything in my path. I’m fast as **** in a chase too, I know all the Shortcuts, a Skilled Jockey who knows how to hit Full Throttle. I almost have a sixth sense for danger and I’m Constantly Vigilant.

My staple gear is a suit of highly advanced armour, a cape, grappling hook, throwing stars and a beast of a car that’s more tank than anything else.

I’m tall, handsome, broody, dark, aggressive and talk in a gravelly voice. My days are spent running a mega corporation, my nights fighting Gotham Cities worst. When people ask why I do what I do it’s “Because I’m Batman!”

Read through all the tips in the superheroes section at the end of the CRB, including balancing the match of superheroes to supervillains, picking a suitable two from the six super-characteristics and downgrading those sub-minions (weaker less gifted mortals).

For both superhero and supervillain build up their 'versus' (see page 237 CRB) would also be my approach, to balance out all that extra can-do will-do awesomeness give them some real opposition that isn't just their opponent.

Often person vs self is really important in these kinds of settings but you probably want to play a lot with some of the others so their challenges aren't just very easy wins.

So pick a few of these kinds of ideas for their background/situation:

vs person: superhero(es)/supervillain(s) = super PCs but also super NPC rivals, a nemesis to match!

vs society: maybe society doesn't like such vigilantes and prefers to do its own lawkeeping, or likes the gossip and celeb element, hence the hiding and the masks...

vs nature: perhaps its a harsh environment- you HAVE to be tough to survive, but this stretches your strength and strains even the strongest

vs self: every hero or villain has their history and it's often a troubled one

vs tech/supernatural: maybe because of your super powers those who oppose you fight back with superpowers and military hardware, other tech or the most powerful of magics is used to try to level the playing field, or as mere mortals can't take you down they've tamed dragons, monsters or something else to throw a bigger threat at you

You may find others fit your source or creation

It also works and shouldn't be overlooked that you can JUST have one or the other, there doesn't have to be a 'character' superhero and supervillain, and they can sometimes be more subtle but still fall into a similar category: a supervillain could be a big monster with no opposite superhero, a superhero could be a smart political player who unites a high-conflict world where there opposing view makes them target number one for example- in one-sided supers like these the other 'versus' that apply effectively take the place of their nemesis rival, a united population can take on that big monster and so on.

Thus for each side of the super- villain or hero- what can circumstance and their rivals do to scale back the super which plays into why they need to be super and the story of who ultimately is supreme, in a lot of ways superhero RPG works like convential RPG, just with the volume turned up to 11.

Probably one of the easier things to do in order to handle superpowers, especially super strength, is to introduce separate power trees (in the same style as Force powers) which allow the character to deal damage on vehicle or planetary scale if they have super-strength (10x damage), and treat their soak as planetary scale if they have super-endurance (10x soak). You could also build those "power trees" to include upgrades which apply weapon or armor qualities to melee attacks and personal defense.

For super-speed, you could rule that hitting a character with super-speed either increases or upgrades difficulty, or if you're dealing with The Flash or Quicksilver, then hitting them is treated as an Impossible difficulty task (requires a Story Point to even attempt versus a massively-upgraded difficulty, no chance of using more story points to upgrade, though party members could assist). Further powers/talents in that "tree" would allow higher difficulty to hit, more actions per round, and so forth. You might even consider making a speedster's attacks treated as minion groups, in a sense, for how they upgrade and damage against targets (because he's doing so many things "at once", like a minion group would do).

Another option for heroes could be to open up the Adversary talent to them at Tier 3, stackable, and possibly rebranded to "Heroism" or something suitably cool-sounding.

I wouldn't break attribute caps, though, except through Dedication. Especially for super-powers of the same "band", one person having Brawn 3 and the other having Brawn 4 represents not only raw power, but their ability to use it effectively.

I would, though, start PCs with more XP in a superhero campaign. How much, depends on your theme, with 100-125 XP for "gritty" heroes, 150 for city-scale supers, and 200 for planetary supers. Mind, the ACTUAL Superman, Wonder Woman, and Batman, played straight, would start with significantly more XP. Builds based on actual comic book characters should just not care about XP, because they're hard to balance anyway in any serious way.

Or at least talents that do those things:

Super Strength: T2, Ranked. Objects of Silhouette up to ranks in Super Strength can be lifted. Additionally your normal Encumbrance Threshold is now 5 x your Strength.

Improved Super Strength: T3, unranked. You may now throw objects you can lift as an Athletics (Brawn) combat check up to medium range, dealing 10 x Silhouette Damage to the target.

Supreme Super Strength: T5, Unranked. Increase the range you can throw objects to Planetary Scale Medium Range.

By building it into the standard talent pyramid you ensure that a characters super powers contribute to their overall growth. If you separate it then you’re saying that they can either advance as a character or advance in Super Powers. Which to me seems out of place.

It's probably not as challenging to set up as it may seem- for existing heroes / villains you can reference what you know about them, their environment/background and how they take on their enemies and vice-versa, making up your own heroes/villains you just see where to go with inspirations from existing ones.

Then work out how best to fit that to the system.

Remember in RPG's you don't have to have rules for everything unless you need them- some info may just be background that can be called on if needed. Often the circumstance will point to an existing rule you can use.

This prior thought may point out anywhere you might need something prepared though- so it could be useful to think what your players may want/need to do as well.