Humor and horror are much more down to the playeds for a TTRPG.
A well written module or TTRPG system can't make someone who is not great with comedy funny, nor can it make a session or campaign scary in and of itself.
No, a module can't make someone funny or the game scary in-and-of-itself, but it doesn't really need to. They can certainly get you a long way towards where you want to go. It's really not that hard to do either.
One of the groups I game with are all semi-pro improv comedians with the exception of myself. In some of my other games ans friend groups I'm considerd funny here and there, but not in this one by comparison of skill level. The improv crew is running a homebrewed Vecna Eve of Ruin module. I don't think that module is written to be comedic, but those comedians make every session goofy and hilarious.
Sounds like an absolute treat.
Horror is more realistic in TTRPGs, but can still be tough to do.
I've run Call of Cthulhu for decades and I've found the opposite, really. It's much harder to create and maintain a horror vibe across a session, to say nothing of a campaign, than it is to create a humorous vibe. Horror is much harder to create and sustain while also being much more fragile. Especially in the face of humor. For humor to thrive, you just have to leave the players to their own devices and poke and nudge here and there. In contrast to horror, humor is easier to create and sustain and practically undead it's so hard to kill once it starts.
The meme of a start of a D&D campaign being Lord of the Rings but the end of a campaign being Monty Python and the Holy Grail is just true.
But combining them? I don't think you can sell a product that makes a TTRPG session both funny and scary. That's really down to the players.
I love the occasional horror comedy fulm like Scream, Cabin In The Woods, Obsession, but don't think the genre mix translates well to this hobby in a way that can be sold.
They exist. So it's not impossible. It just takes a bit more work than most other RPG products.
For example: Ghostbusters, Eat the Reich, Paranoia, Tales from the Crypt, Demon Hunters, Human Occupied Landfill, Laundry Files / Laundry, Call of Catthulhu, etc.
It also depends a lot on where along the spectrum of horror-comedy you're talking about. 1% horror, 99% comedy. Once Bitten is horror-comedy. Ghostbusters is horror-comedy. Gremlins is horror-comedy. Shaun of the Dead is horror-comedy. Tucker and Dale vs Evil is horror-comedy. American Werewolf in London is horror-comedy. 99% horror, 1% comedy.
I'd argue it's easier to do a horror-comedy than either just a horror or a comedy. There's so many more tools to pull from when referencing both. Hell, if nothing else simply mocking or parodying horror tropes would be enough, see Shaun of the Dead. Or exaggerate them to the Nth degree, see Tucker and Dale vs Evil.
