Riven's golden dome['The Interactive Palette' is a biweekly GameSetWatch-exclusive column by Gregory Weir that examines the tools and techniques of the digital games trade with a focus on games as art, using a single game as an example. This time - a look at puzzle design in the Myst series.]

Puzzle. The word has many different meanings in the context of video games. The term "puzzle game" can refer to a game in the mold of Tetris; there are many shaped or colored blocks or jewels or bubbles that must be cleared by manipulating them within a time limit. In this context, the "puzzle" tests the player's coordination and reaction time.

However, the word "puzzle" is also commonly used in a broader and more conventional context to describe an intellectual obstacle in any video game. When the developers of Half-Life 2 break up the shooting-and-driving gameplay to have the player assemble a makeshift ladder, that's a puzzle. So are the ubiquitous sliding-block puzzles of Zelda infamy. In these cases, puzzles are intended to serve as pacing devices, allowing a moment to relax and think in the middle of all the killing.

However, there are categories of video games where the game is entirely composed of puzzles. One group is games like Chip's Challenge, 3D Logic, or Portal, which all present a sequence of similar puzzles differing only in complexity and scale. However, to the true puzzle connoisseur, the height of the art is to be found in the adventure game.

The Monkey Island series, the Infocom interactive fiction games, and escape-the-room games portray worlds in which puzzles are a fact of life. The developers try, with various degrees of success, to incorporate puzzles seamlessly into the game world, so that players can inhabit a character who thinks her way around difficulties rather than shooting her way through them.

In the adventure game category, few games are more maligned than Cyan Worlds' Myst series. Spanning five single-player games and one repeatedly-resurrected online game, Uru, the Myst series is often blamed for bringing about the death of the adventure game. It popularized the concept of a silent, faceless protagonist exploring an uninhabited game world, and led to a myriad of copycat games where the atmosphere was spooky but the puzzles were arbitrary and banal. These concepts were anathema to fans of the character depth and humor of the Sierra and LucasArts adventures.

However, it really is the puzzle-solving where the Myst series shines. By looking at the best (and worst!) puzzles of the series, we can gain an understanding of how to construct truly compelling intellectual challenges. For a puzzle to be effective, it must be three things: fair, novel, and integrated.

AmateriaA Fleeting Glimpse

First, let's look at my three favorite puzzles from the Myst series. These are Riven's marble puzzle, Myst III: Exile's Amateria Age, and Uru: The Path of the Shell's Ahnonay Age. All three require observation and logic, then reward the player with an "a-ha!" reveal. Below, I'll discuss the setup and solution to each puzzle.

The marble puzzle is the trickiest challenge in Riven, the second game in the series. In order to restore power to the mystical linking books that lead to the villain's haven, the player must enter a combination into a device on Dome Island. Luckily, the villain has an unreliable memory, and has based the solution on the geography of the game world. The player must place five marbles in a grid, with each marble's color and location matching that of a small dome encountered over the course of the game.

Part of this puzzle's genius is that it brings together all of the challenges surpassed so far in the game. In order to know the locations of the small domes, the player must have solved all of the earlier puzzles which provide access to the domes. Discovering the associated colors requires the player to have determined which symbol matches each color, and which dome matches each symbol.

At a few points in the solution process, a process of elimination is required to account for damaged machinery. The solution requires a full exploration of the game world, over five leaps of associative logic, and the use of several devices to process and sort the proper information.

Trial and error would get the player nowhere with this puzzle; there are thousands of possible combinations, and only one correct one. The puzzle is fiendishly difficult, but it isn't unfair; every aspect of the solution is prominently clued somewhere in the game, and all the player needs to do is put the clues together. Many players, including myself, required more than one hint to solve the puzzle, but my reaction to the solution was "Why didn't I see that?" rather than "How could I have been expected to see that?"

Amateria is one of three main puzzle worlds in Myst III: Exile. It is an island with hexagonal geology and enormous crystal spheres that roll along metal tracks. In a series of preliminary puzzles, the player must get spheres to traverse short patches of tracks, using simple logic to disable obstacles. This provides access to a central control station, where the player discovers that the three short stretches of tracks are connected, and must arrange a route so that a sphere can roll through all three tracks in sequence.

Finally, when everything is set up properly, the player discovers that the tracks are more than puzzle elements; they are a transportation system. The reward for solving the puzzle is a roller-coaster ride through each of Amateria's puzzles, finishing at the part of the world that the player has been trying to reach the whole time.

Like Riven's marble puzzle, Amateria's final puzzle brings together each of the previous puzzles of the Age. The player must have solved each puzzle and understood its solution in order to complete the challenge. Beyond that, the puzzle is based on real-world principles. Amateria does not just ask for a secret password which magically opens a door; the player is constructing a path for herself to take to her goal. Beyond that, the reward of the roller-coaster cutscene is one of the most exciting and good-looking sequences of the series.

Finally, Ahnonay is one of the worlds from the Uru expansion, The Path of the Shell, as well as being included in a modified form in the short-lived, GameTap-sponsored Myst Online: Uru Live. This Age was constructed by a charlatan named Kadish to fool people into believing he had power over time travel.

When the player first enters the Age, it has been abandoned for some time; she must use a description of how the Age used to work in order to experience Kadish's illusion of time travel. By experimenting with objects in the world, the player finds that Ahnonay is nothing more than a soundstage that is somehow being transformed from one "time" to another.

Diagrams within Ahnonay suggest a fourth "time" that is not part of the usual tour. By combining the player's knowledge of how travel between worlds works with the controls found behind the scenes, the player can reach an observation room outside of the entire structure, where the true nature of the world is revealed.

There's nothing mystical about Kadish's trickery. He simply built a huge device which rotates each "time zone" into place in preparation for a group's arrival. There are four separate soundstages, each one able to be rotated in and out of the active position.

The player's progress through Ahnonay works on two levels. As the player solves small puzzles within the Age, her understanding of the mechanisms behind the world grows. At the beginning, Kadish's illusion is powerful, and the puzzles within seem impossible. By the end, the player has solved all of the puzzles and understands the mechanism behind the Age's trickery.

Each of these puzzles — Riven's marble puzzle, Myst III: Exile's Amateria Age, and Uru: The Path of the Shell's Ahnonay Age — is memorable and compelling because of certain qualities they share. By looking at these qualities, we can better understand how to construct equally effective puzzles.

AhnonayNot Yet Been Written

For a puzzle to be a good one, it should be fair, novel, and integrated. A fair puzzle is one which can be solved using information and tools provided in the game, without depending on guesswork, specialized knowledge, or a walkthrough. A novel puzzle is one which is unique to the game, not a reskinned version of one the player has seen before. An integrated puzzle is one which can believably exist in the game world, and which has appropriate in-game consequences.

For a puzzle to be fair, it should be possible to solve it using only information provided in the game and accompanying materials. It's fine for a puzzle to require things like basic math and logic skills or the fundamentals of gravity and electricity, but more specialized knowledge should either be avoided or provided in an in-game text.

In Graham Nelson's "The Craft of Adventure," he cites Zork II's diamond maze as an example of an unfair puzzle; it requires knowledge of baseball, which is uncommon outside of America. This is a mild offense, but imagine a game which assumed knowledge of medieval heraldry or Indian Carnatic music. In the worst case, a player might not even notice a puzzle existed, which would mean she wouldn't know to look up the required information in an external source.

Additionally, a puzzle can be unfair because it requires undue guesswork. A puzzle solution that only makes sense after the fact is unfair, as is an unclued, arbitrary solution like Dare to Dream's use of a fish tail as a key for a door. Generally speaking, if a walkthrough is the only way to figure out a solution, then the developer is being far too clever. There should be a continuous trail of logic from the clues to the solution.

Novelty is also important in puzzles. At some point, the boxes-on-a-slippery-surface puzzle was novel. Not anymore. Any experienced player who encounters one of these puzzles knows the way to solve it; she just needs to carry out the solution algorithm. There's no intellectual challenge, which makes the puzzle nothing more than a time-waster. The same goes for a sliding tile puzzle (or "fifteen" puzzle). As a general rule, if a puzzle is included with the default installation of your operating system, it's not novel.

Novelty is important because the fun and challenge of a puzzle is in discovering its solution. Just implementing a solution the player already knows is pointless. Nor is it enough to just dress an old puzzle up in new clothes. A Tower of Hanoi puzzle is not made new again by making the disks precious coins or UFOs. It might be acceptable to do something clever like make the disks actual floors of a tower that could be navigated in different configurations... but only as a last resort.

The final requirement is integration. Players are perfectly willing to accept a world full of absent-minded folks who write down the combination to their luggage in code, but there are limits to their credulity. Take 7th Guest, which is famous for its puzzle in which rearranging soup cans opens a door. This is a game where ghosts are evidently murdering other ghosts, and the puzzle is still hard to believe. At the very least, a puzzle should make sense in the game world.

More than that, though, a puzzle should fit. Most of Myst's puzzles suit the game world; there is a reason for them beyond the game designer's need to challenge the player. The series' use of Ages, or dimensions, helps with this by providing a strong theme for sections of the game. Channelwood's puzzles are related to the water-based power system used there, while Kadish Tolesa's puzzles all feel like they were created by a conceited and slightly crazed con man.

Fairness, novelty, and integration are all important for making good puzzles, but what makes the puzzles discussed here stand out is their payoffs. Each of them has a moment of epiphany, where the odd structure of the game world suddenly makes sense, and all the pieces fit together. Because they are especially tricky, the reward is sweeter, and the player feels a greater sense of accomplishment.

It's this puzzle with a twist that is the greatest strength of the Myst series. By starting with a solid puzzle and then adding a twist, developers can make their own puzzles stick in players' memories. This doesn't just apply to adventure games, either; any kind of game that uses puzzles will be better-served by a cleverly crafted obstacle rather than just another game of Nim.

[Gregory Weir is a writer, game developer (The Majesty Of Colors), and software programmer. He maintains Ludus Novus, a podcast and accompanying blog dedicated to the art of interaction. He can be reached at Gregory.Weir@gmail.com.]