The Explore Challenge is difficult in the same way that I Wanna Be The Guy is difficult.
This is to say, it's a level built around the idea of using brute force to solve it. It has a couple of (surprisingly good) puzzles and that's it for the part that's actually challenging; the rest of the level is just made to be annoying, or, at the very least, unfair.
It's quite a good method for concealing a cheat, since the people who are unlikely to use the cheat much anyway are going to play through the level and get it the "fair" way, and the people who are going to use it to cheat their way through every level they play are going to either look in the level editor or just Google for it.
EDIT: No, seriously, I figure that's the best way to hide a cheat.