I think he meant my whole future continuation of this mod in general, not just your additions. No, I'm not planning on having any secrets that are insanely hard to find. HOWEVER, I am planning on having there be three different endings to this, and I do intend for a small amount of secret finding to get the best ending. But it shouldn't be anything too hard to figure out, and it should be all the easier to figure out if you've saved curly in Cave Story, which probably everyone playing this mod has. In one of the endings, you drown after the fight with the core, after sacrificing your life to save Quote. In another one, you panic after Quote destroys the core, and die when the island falls. And in the third one, like Kaeso intended for this mod to end, you get found by Quote in the sacred grounds, and defeat Ballos. Preventing your death after the fight with the core might not happen if it's that person's first playthrough, but I'm planning for it not to be TOO hard to figure out how to prevent it.
Speaking of Jenka's Nightmare, yeah. Some of the secrets in Jenka's Nightmare are pretty insane. I've yet to figure out where all the pieces to the puzzle are, and how to get the Nemesis X without hacking the game. Also, I've only gotten three out of the four endings it has. And the only reason I found the sky blade was cause of the guide. So I'm not going to make the best ending in this mod that hard to get.