The key to any puzzle is the "aha" moment, that moment when everything clicks into place, your brain gets a little jolt of pleasure and you feel just a tiny bit smarter. The final few numbers in sudoku, grasping the bizarre logic of Sam & Max, figuring out exactly where to put the next portal -- it's these moments that make puzzles worthwhile.

A puzzle with no "aha" is like a nut with no meat. You go to all the effort to crack open the shell, only to discover there's nothing inside. In nine hours of Trine 2, I've piled up a lot of shells, but not enough meat.