Something I’ve mentioned but not really explored is that I think puzzles aren’t actually games. I’m fine with the moniker, “Puzzle Game” as a misnomer referring to a collection of puzzles and I think “Action Puzzle” like Tetris are games, not puzzles (except in B-mode, where it becomes a puzzle)
Basically, there’s a spectrum of Riddles, Puzzles and Games, which each play on a similar root desire of, “Try to make the thing happen,” but with different emphasis. Puzzles and Riddles are subject to the spoiler effect. Once you know the solution, it’s not a question of whether you can beat it or not, you can always just produce the solution, unless you forget it. This also means that someone can tell you the answer and there’s no challenge anymore.
A Riddle is essentially asking a question to which an answer must be inferred or intuited. A Puzzle creates a system of logic from which an answer must be deduced. And a Game creates a system of interactions which must be manipulated to produce a positive outcome from many possible inputs or “solutions”. You could also probably fit Contest in there, which creates a single interaction that must be manipulated over a certain threshold.
Riddles essentially have a specific answer and a hint as to what the answer is. The hint can be more clear or less, but the key defining feature of a riddle is that the relation of the hint to the answer isn’t definitive. You can’t entirely logically prove that a given answer is valid or invalid.
Who makes it, has no need of it.
Who buys it, has no use for it.
Who uses it can neither see nor feel it.
What is it?
The answer is a coffin (maker isn’t dead, neither is the buyer, dead guys can’t sense). Or mind-numbing drugs (drugs are bad, nobody needs or has use for them). Or therapy (therapists don’t need it, insurance pays for it, it’s not physical). Or you could probably come up with a lot of other answers.
Phoenix Wright is a game built on Riddles, and Professor Layton is a game mostly built on Puzzles, with a bunch of riddles thrown in. At their best, riddles can have a clear and consistent logic, while also concealing their answer, and very clearly corresponding to the correct answer. Phoenix Wright is very clever about this, making it so you need to point out contradictions. What qualifies as a contradiction is very open ended, and not immediately obvious, but once you spot one, it’s entirely clear what the contradiction is. Of course, even in Phoenix Wright, the answer to each riddle isn’t always clear, due to differences in the quality of writing making the hints less clear. And of course sometimes the connection between things is inane, or things that seem to be contradictions aren’t the answer. Or it’s possible to notice contradictions before they’re the right answer.
One example of a riddle as opposed to a puzzle would be in Ocarina of Time. In Dodongo’s Cavern, there is a large stone block surrounded by bomb plants, with a gap in the line of bomb plants at the center of the block. If you place a bomb here, it will detonate both lines of bomb plants, causing the block to collapse into a set of stairs. The block will not response in any other way than you placing a bomb at that spot, and this interaction is not repeated anywhere else in the entire game. There are no destructible walls that bombs normally interact with. This requires a leap of intuition that the developer wanted you to place a bomb here, rather than any logical connection between previously established rules.
Adventure games, such as point and click adventure games, are generally composed entirely of riddles. I’d personally attribute the downfall of the genre to needing to make difficult riddles, which lead to increasingly absurd and inane hints and ultimately no one wanting to put up with that anymore. Making a riddle difficult is a process of burying the lead. Making a riddle fair is a process of establishing consistent criteria for a correct answer that can be extrapolated upon. This shows why Phoenix Wright is so successful at the adventure game format, pointing out contradictions is extremely clear and consistent, but also allows for contradictions to be extremely subtle, yet it’s (almost) always clear what is a contradiction and what isn’t.
Puzzles, like riddles, aren’t about making interesting choices or testing execution, so much as they’re about having a system and attempting to reason about how the system behaves to produce a small set of discrete answers. Riddles are less than that, not having a system to reason about, just the hint about the hardcoded answer (meaning, the answer is simply set to be what it is arbitrarily, not dependent on anything else). Puzzles can have hardcoded answers, but more frequently they’re a system set up to only allow a certain solution.
I think riddles and puzzles aren’t games, because games typically involve repetition and consistency. Games can involve randomness and wider divergence of answers, with less rigor applied to mistakes. In The Witness, you’re frequently required to repeat puzzles when you fail to answer one, but because of the spoiler effect, you already know the answer, so there’s little to no question of consistency. As long as you know the answer, you will always be consistent. It’s not rating your general skill, it’s just asking you to produce a valid answer on your own time. Some sections later in The Witness employ randomly cycled puzzles on a time limit. These are more game-like. Games typically employ some element of randomness to their challenges, or test your execution skills so you sometimes succeed and sometimes fail, sometimes in different places. Knowledge may increase your consistency in a game, but knowing one weird trick shouldn’t let you beat any part of a game with perfect consistency, at least not by itself. A game is a series of interesting choices, and a puzzle is about finding the solution, not making tradeoffs.
Since Puzzles and Riddles are not about consistency and repetition as much, I think they need to be judged by different standards than games. Depth obviously isn’t as big an issue in puzzles as games. Having a large state space can be important to a puzzle, to prevent its solution from being brute forced, but it’s not inherently a good or bad thing, where I think it’s inherently a good thing in games. For this reason, I think what makes a good puzzle is more subtle than what makes a good game, and I don’t think it’s really in the scope of my writing.
As said at the start, this is a spectrum. Something can be more riddley, more puzzley, more gamey, or somewhere inbetween. Catherine has elements of both, as stages have multiple solutions, but do emphasize a limited set of solutions, and occasionally can be more about interesting choices than finding a specific solution (enough so that there is a competitive versus mode). Plus there are timed elements, bringing your efficiency into question.
I do however think we should avoid riddles in game design. It’s too easy with riddles to either make something signposted so heavily that it’s a chore, or so obscure that it’s impossible to tell what to do next (both of which occur frequently in 3d Zelda and games inspired by 3d Zelda).
tl;dr: Riddles are about “guess the thing, here’s a hint”, puzzles are about “here’s how some stuff works, now do exactly this with them”, and games are about, “Here’s how a bunch of stuff works, now make them get to here”