D&D 5e with superheroes?

[coba]

I personally really love D&D 5e, the way it handles combat, and the simplicity of it all. I play a lot of GURPS, CoC, and 5e these days, and have had an itching for a superhero game. I have some players, MCU fans, who want me to run them through a fun D&D-style superhero game. I said I could totally do that, then came down to working on it.

I'm not a fan of M&M, and my players really want to play a reskinned 5e. I started to lean towards Silver Age Sentinels D20, but that game seems to be more based on 3.5e. I've taken it upon myself to sort of merge SaS and D&D 5e into a coherent game. This has proven difficult.

My main focus was to work it like this:

PCs with high strength and low speed would have one attack per turn that can deal devastating amounts of damage. They would also have high HP, but low ACs, so they get hit a lot and just shrug it off. (Barbarian, but with even higher HP).
PCs with average human strength and average human speed would need some sort of armor or gimmick (Iron Man or Hawkeye) that grants them damage resistance, damage sources, and have combat training that grants them an extra attack or two. (Fighter, Ranger, martial classes).
PCs with average human strength and superhuman speed would have many attacks per turn (see monk, flurry of blows) that all deal relatively low damage. They would also have relatively low HP, but higher ACs due to being hard to hit. (Monk and Rogue).

I've made my own custom systems before, but I can't seem to figure out how I can make a D20 with a point-buy system that also supports such high ability scores (Strength that can deal 60 damage in one hit, Dexterity that grants absurdly high ACs, etc). I have all these ideas but I can't seem to balance this right.

My main thought was to cap these abilities pretty low. "Your maximum AC can be 22, no exceptions," or "Your Dexterity can only grant you 6 extra attacks," "This Power (feat) also grants extra attacks," "You can only have 6 extra attacks, no exceptions," etc. I'm having a lot of trouble here.

Does anybody have some tips, ideas, recommended literature, or even another game system I could have an easier time adapting? I've been pulling my hair out trying to do this, something keeps telling me I'm just missing something.

Thanks in advance.

[GalacticAxekick]

I don't think you need to make PCs any stronger for them to feel like Marvel heroes. Instead, keep commoners around "for scale". Players will feel invulnerable when they have dozens or even hundreds of hit points and the power to knock crooks out with a flick of the wrist. Monsters and NPCs with class levels can represent supervillains who rival the players.

Remember that hit points represent survivability, not ability to withstand damage.
The same way a PC with 200 hit points cant actually shrug off dozens of arrows while a dragon with 200 hit points totally can, the hit points of a durable hero like the Hulk is represent something different than the hit points of a nimble hero like Hawkeye.

If you really want a player to he vulnerable at least some if the time (like Iron Man without his armour), the their class features to an item or action. The same way that a Druid uses Wild Shape to gain the Strength, Dexterity, Constitution, HP and other statistics of a beast, maybe Tony Stark uses Don the Armour to become a nth level Wizard with full plate.

[Amnoriath]

Well first and foremost since you are using 5e we can't treat the base ability scores as reasons for super strength, super speed...etc. Either the numbers will increase way too for advantage and disadvantage to matter or the numbers represent way too much making ordinary humans catch up way too much just to get the right numbers.
Instead we need to represent them seperate as levels. The levels don't add numbers to your d20 roll instead it interacts with other levels or lack there of. Example when someone has a higher super strength level they have advantage on strength checks against that creature. It increases damage in general and they may levels advantage to increase distance pushed, rendered prone...etc It would also multiply carrying capacity and could change base dc of tasks.

[GreatWyrmGold]

The design goals of a game system should always include aligning mechanics to whatever the game is supposed to "feel" like. This is true on both a macro and micro scale.
For instance, Dungeons and Dragons is focused on bringing characters from a merely exceptional individual to a godlike hero, which is why it has a leveling system.1 Meanwhile, a system like Shadowrun doesn't intend to have that sort of sense of character progression, so its equivalents to XP and levels (karma) is much less prominent.2 Call of Cthulhu wants to allow some measure of going from ignorant nobody to less-ignorant occult investigator, so it has systems for improving your skills more significantly than you usually can in Shadowrun, but to a lesser extent than D&D. You also see this design intent in even more fundamental building blocks like intended odds of success and the consequences of failure.
D&D is intended as a relatively lighthearted experience, and makes the chance and consequences of failing any individual roll relatively low.3 SR is intended to be grittier, as you would expect from cyberpunk, and makes the potential consequences for epic failure (and, for low-skilled characters, the chance of it) much higher. And CoC? It's horror, and that means that there's a good chance you'll fail anything your character isn't skilled in, and failing the wrong roll can mean instant maiming or insanity...or worse.
And, of course, you have the more "extraneous" elements—for instance, magic in D&D,4 cyberware in SR, and insanity in CoC. You could theoretically remove one from a system, or with a bit of work make it fit in another system, but the results won't be pretty. Major elements usually worm their way into other parts of the system, in particular the expected tools one has to tackle various challenges. For instance: No spells in D&D means only a few classes (or most get a serious debuff), no healing magic to recover from fights easily, and no crowd control; no cyberware in SR means nothing for mundane characters to invest nuyen in to compete with the power magicians wield at high karma levels; and no insanity in CoC not only ruins the tone, but removes balancing factors for countless other elements (particularly Mythos Knowledge and magical spells).
In short, modifying systems for purposes they were not designed is hard if you want a result that fits well.

Adapting D&D to a superhero setting has several obvious issues. Off the top of my head...

Superheroes are unique, but D&D heroes are fantastic archetypes. Without approaching every-3.5-splatbook levels of options, you're not going to make a class-based system like D&D get particularly near the diversity of powers offered by a point-based system like GURPS or Mutants and Masterminds. Speaking of which, you would need to make several new classes, since options like "big, dumb brawler" are not supported well (unless you think the Hulk is a monk).
As mentioned, D&D is built around heroes becoming more and more powerful over time. This is not an (intentional) element of (most) superhero stories.5 This isn't a deal-breaker, but it's certainly not good...especially since it massively increases your workload for each new type of powerset.
D&D is largely a game of resource management. You have a certain number of spell slots, hit dice, class ability uses, etc etc to use each day, and can recharge some of them with a long rest. Superhero stories don't really have this, and very rarely tied to their primary abilities. Most of the time, superheroes just keep going, able to make full use of their powers until their fatigue or injuries start to get in the way—and sometimes even beyond that, since succeeding through pure willpower is a common trope in superhero stories. The exceptions (whether it's Hourman's time limit or Spider-Man's limited webs) are almost always treated as exceptions, and those superheroes don't usually worry about it most of the time. In other words, while D&D builds resource management into its core balance, while superhero stories only inject them when it's dramatically appropriate.
Gear is not as important in D&D Next as in most prior editions, but it's still pretty important (especially those early armor upgrades). Superhero stories don't really have that; most heroes rely on their ow inner strength with minimal aid from external aid6. Plus, as previously noted, upgrades in general aren't much of a thing in superhero media.



TL;DR: It's probably easier to throw together your own system from scratch than modify D&D to fit a radically different setting and narrative.
Though, luckily, some people have already done this sort of thing. ParaLite, (https://docs.google.com/document/d/1s1KOEawbIqVd2e5kuCNxVHfW871p0yVqZGBN4xuHlC8/edit?pli=1) a system designed by the Worm fandom, might be a good place to start. (Though it is, as the name implies, rules-light, and its big brother Weaver Dice has a lot of Worm-specific baggage to it.)


1: Well, it's probably more accurate to say that it has a leveling system to reduce the initial barrier to entry while still maintaining the potential high-fantasy complexity, and later editions leaned more into that sort of progression. But design can be a two-way street like that.
2: For the most part. And better gear still allows some advancement, but again, that fits the mercenary tone of your typical Shadowrun game.
3: Aside from the various save-or-lose spells, which...well, they're hated for multiple reasons.
4: I mean, Shadowrun and Call of Cthulhu have magic systems, too...but let's not focus on those. Though I could easily write paragraphs about the differences between their magic systems and the implications this has for tone.
5: Many heroes, such as Superman, have increased in power over the course of their existence by simply having more writers either give him more things he can do ("Now he has cold breath/X-ray vision/super-weaving!") or simply pushing the boundaries of his established powers (pushing planets when he once struggled to lift cars). Some, like the Invisible Woman, had a similar thing happen more intentionally; "Sue's pretty useless, let's give her force fields." In neither case is a superhero becoming more powerful an important element of the narrative; superheroes usually remain at about the same level of both power and importance for their entire lives, barring big shakeup events (e.g, the Falcon taking on the role of Captain America) or reboots.
There are a few exceptions, but most are discrete plot-defining (and usually temporary) upgrades like Spider-Man's Venom costume thingy or nominal upgrades that rarely affect the plot significantly (like Iron Man's constantly-iterated armor, which sometimes lets him beat up bad guys in more interesting ways but never seems to make him significantly better at it). The only exceptions I can think of off the top of my head are My Hero Academia (which, naturally, draws as much from typical shonen as it does from Western superheroes) and Worm (which is more about learning new ways to use her powers than actually getting new powers).
6: Which is why nearly all tech-based superheroes invent their own technology.