Masters of the Universe are by Mattel, a rival company. They tried a merger but they couldn't reach an agreement.
Of course we know injuries in the real life aren't so easy to be healed as the videogames or fiction.
We are in the age of videogames, where the players with enough experience in some battle royal know the difference between a simple gun and a machine gun. We should remember it is not only the PCs but also the enemies with firearms can be broken thanks/by fault of modern weapons. A simple gobling with an axe and a shield is not the same level of menace than the same creature with identical stats, but this time with a sniper rifle from the roof of a house.
And firearms can be in a survival horror, or in a battlefield campaign. The power level can be very relative.
In the movie "Cobra" the female character, played by Bridgitte Nielsen couldn't face the bad guy, the "night slasher", only hide and run away, but in the final confrotation the main character, played by Silverter Stallone, with enough ammo, he could face and terminate the cult of the new dawn. In "Alien the eight passenger" only one xenomorph was enough to kill almost all the Nostromo staff, but in the second movie dozens, maybe hundreds of them were killed from other room thanks the sentinel turrets. The first time Robocop faced the robot ED-209 he bit the dust and had to flee, but in the end of the movie only a shot with the cobra assault canon was enough to destroy it.
If you allow firearms in your d20 game, then the builds focused into hand-to-hand fight (monk, barbarian, paladin) will be replaced by the gunslingers. The characters from "Street Fighter" can't face ones from "Overwatch", or fighters from Mortal Kombat can't face monsters from "Doom".
D&D is not ready for crossovers with no-fantasy franchises, but if these suffer a mash-up adaptation style Rwby x Justice League or DC Dark Knights of Steel.
* Somebody says the old days of glory for Warcraft ended. Maybe WotC could publish a 5e version of Warcraft.
* D&D cosmology should add something like a "legendland", an alternate continuity created with the collective fiction.
101 appearance(s) of Ideaverse 1 minor appearance(s) of Ideaverse 1 mention(s) in handbook(s) of Ideaverse 256 image(s) of Ideaverse 78 characters that originate from Ideaverse 2 teams that originate from Ideaverse 5 organizations that originate from Ideaverse 10 locations that originate from...
marvel.fandom.com
* How would be a crossover New Capena(Magic the Gathering) and a mash-up diesel-punk version of M.A.S.K?