That's fine, but the fact that most of the corridors just don't lead anywhere kind of destroys that feeling of "I've uncovered a new section, let's see where this leads!...oh, it's a dead end. Well, maybe this corridor will...nope, another dead end." In the end, it simply wasn't compelling in any way. I didn't feel like I was forging a path through uncharted territory and uncovering a strange new world. The tedious backtracking was also ten times worse given the size of the map. As much backtracking a Castlevania has, it pales in comparison to Knytt.
As for the story, I try not to think about it anymore. If it was being a parody of game narratives, it fails pretty hard. I don't want to spend ages completing a quest, only to "fail" it. When I complete a quest, I want to feel a sense of accomplishment, and one that doesn't just come from that check mark or grayed out text in my Quest Log. See Persona 4: The Golden. Completing quests in that game just felt good, and satisfying.
Still, I agree, Knytt wasn't for me, but it had nothing to do with not having my hand held or grasping the mechanics of the game or what it was trying to do. It just failed at being engaging in any meaningful way. You can guide a player, and still be non-linear and open-ended, and not hand-holding. Many great games do just that (like Demon's Souls/Dark Souls, for example; two games I absolutely love, and have a similarly grand, open ended game design). I guess I'm at that age in my gaming life where I simply don't have the time to spend wandering aimlessly through corridors, trying to "puzzle" my way through a game. Especially in a game that isn't engaging me in any other way. After 15 hours, Knytt just lost its luster for me. That's all there is to it.