Guaranteeing Satisfaction

[Warning: I'm going to make reference to the Babel fish puzzle from The Hitchhiker's Guide to the Galaxy. There are no explicit spoilers, but I do hint at the solution pretty strongly.]

What makes puzzles satisfying is even more subjective than what makes a puzzle fair. I had a lot of difficulty coming up with a list that could lay claim to even living in the same town as "definitive."

Ah, well. What follows is a list of elements which have made me feel satisfied when solving puzzles. Hopefully your list and mine will overlap.

• The puzzle is fair. I'm much more satisfied with puzzles which I feel are fair than ones that aren't.
• The puzzle walks the fine line between too easy and too hard. Sure, this line shifts for me every day, but easy puzzles aren't all that satisfying and difficult ones may send me scurrying for hints or a walkthrough.
• The puzzle knits information together. I enjoy it when a puzzle forces me to re-think parts of the game, even if those parts are not directly related to solving the puzzle.
• The puzzle is in character for the story. One challenge that faces a designer is making puzzles which aren't obviously out-of-place. Adventure games are notorious for having puzzles (like slider puzzles) which don't have any reason for existing other than reaching some puzzle quota. It's as if the designer has said, "Pad the game. Pad the game!"
• The solution is clever. How original is the solution? When I discover it, do I think to myself, "That's really clever"?
• I didn't solve the puzzle by brute force. Trying every possible combination to open a combination lock isn't much fun.
• I didn't solve the puzzle by accident. It's not very satisfying to realize, whoops, I just solved that puzzle without meaning to.
• I make incremental progress. The Babel fish puzzle in HHGTTG is poorly designed in several respects—a time limit and the requirement of an apparently-useless object from the beginning of the game make it well-nigh impossible to solve without a lot of saving and restoring. However, it is one of the most satisfying puzzles I've ever solved. Why? Because I kept having to solve smaller puzzles in order to solve the overall puzzle. Brick by brick I built a solution out of gowns and satchels and junk mail until I had that damned fish. Now that I'm older I doubt that I'd have the patience to solve this one, but at the time I was so happy to have solved it and I felt so smart.
• I have a flash of insight. After I've stared at a puzzle for a while, suddenly realizing what the solution must be is a wonderful feeling.

In my ideal adventure game world, authors and designers would think carefully about what they enjoy about puzzles and then keep that knowledge in mind while designing puzzles. Or, as Dan Shiovitz succinctly put it, think like a player.