i've been binging these - and each one you've talked about as too difficult has felt like exactly the right difficulty to me, while a few have been too easy. i think that a sketch is actually the perfect place to err in the direction of more difficult - a sketch is short, and there's relatively little cost to starting over from the beginning and trying a different approach. (in fact, in valdivia's notes, it seemed like you had the assumption that the player should not have to die to explore, but the cost to dying is so low, so why wouldn't they?) i'm not really sure you even can have a meaningful routing puzzle at lower difficulty than this or valdivia - at least if the only outcomes are death or victory. (the shepherd one had score based on the remaining health of the sheep, and that made it possible to have an incredibly easy routing puzzle to get a c, a somewhat difficult routing puzzle to get an a, and an actually difficult routing puzzle to get an s)
but, my taste and ability may run toward the more difficult anyway. i definitely do want the game to make me engage with its systems and ideas. your work (both these sketches and other games you've published) generally does do that, and that's more than can be said for the majority of jrpgs. but i might not generally be the player you're trying to appeal to with these sketches. i suspect that the audience you already have appreciates your bias toward difficulty though