To tack onto this second part: I was recently talking with my friend while playing, completely distracted, and the game still freaked me out with a sound-based event. So on one hand, yes, we understand that the game is meant to be singleplayer, but on the other, adding a multiplayer option would not affect the overall experience.
That said, and agreeing that the dev shouldn't add it to this game, it would be nice to see it added in a potential other, VotV-like game from the same dev, be it a sequel or a different game.
Edit: Forgot to mention, my friend did ask if he could join, only to be disappointed that he couldn't lol