That's the thing though: arbitrary deaths aren't difficulty or challenge, they're just random. It's masochistic fun, if it is ever fun at all--it is an abusive kind game design. "You will play this until we decide you can pass."
From the RPS WIT of Rain World, I actually get the sense it's going for a Zelda: Breath of the Wild (or perhaps, Toki Tori 2+) kind of exploration and discovery, only without the sublime design that makes those games such forces to be reckoned with. They, you see, have signposting (as in, puzzles) everywhere to uncover new mechanics--it's just up to the player to recognise them and try something. BotW in particular also has loading screen tips and NPCs that illucidate things further. Both are really good at what they do in terms of naturalistic, non-verbal teaching.
...Yes, everyone should play Toki Tori 2+, the Dark Souls of puzzle-platformers. Forego the white meatball for the yellow one.