Because of this fact, I can only imagine how difficult game design must be (particularly puzzle games). The "perfect" experience is for the player to have just

Because of this fact, I can only imagine how difficult game design must be (particularly puzzle games). The "perfect" experience is for the player to have just enough difficult figuring out a solution that they feel clever when they succeed. I remember feeling this way several times in my first play-through of Portal, but then I remember Portal 2 feeling way too "guided" (sometimes even easy), as if they had play-tested it to death.