For the puzzles, I have noticed something, a lack of a certain type of puzzles.
The kind where you have to fiddle with a gizmo according to certain rules on what moves are legal until you end up with an accepted solution.
An example of this kind of puzzles would be Binary. Or a Rubiks cube if you want a more popular example.
I simply find it enjoyable to sit down and have to figure out what moves to do in order to reach my goal. It allows you to get accustomed the puzzle and the limited moveset means that you need to think several steps in advance most of the time.
True, you can accidentally solve the puzzle, but while the player does not know the moves he used to solve it, he usually has a vague idea of what he did. The puzzles simply are complex enough that you need a strategy or you will end up getting nowhere.
I realize that it will be a problem finding a scoring method for such puzzles, but who cares about the score?