There are apparently a lot of people who play this game and have difficulty figuring out what the fuck you're supposed to do. That factoid is the pearl of this game, and an indictment of the way the games industry has trained its population of players. It also says something about the algorithm of human stupidity. This is a game that is fun because of how you relate to it, relative to how other people relate to it.
Basically, the same skills this game tests are what our public schools try to cram down your throat, and yet don't succeed nearly as well as a five minute Flash. Just take in information, pay attention, and then use that information to determine a solution. It's a pretty fundamental process, you could call it the scientific method, or synthesis, or in some contexts, common sense. It's also on of the fundamental ways that games engage people cognitively, such as the way people observe why Tetris blocks disappear and then fold accordingly, or the way people observe crime and pollution and housing prices in SimCity, and try out a new zoning pattern. You found the grappli... I mean You Have To Burn The Rope takes this process and flays it out for you, cured and dried, like a nice piece of jerky wrapped in fresh leather.
The ending song has drawn plenty of comparison to Portal. What's interesting about that comparison is the ways this game isn't like Portal, namely all of them. What they have in common is a purification of this cognitive cycle of synthesis and adaptation. Portal builds off the complexity of its components after gently introducing you to them one at a time, and sure, GLaDOS might compare to the instructive text here, but then again so would Shodan, or that really obtuse narrator from Ultima IX. YHtBTR is the inverse of Portal, a veritable enema of complexity, and yet, there in the remnant is: Mini-Me.
Am I getting through clearly? You have to burn the rope.