Game Design Essentials: 20 Mysterious Games

Following three previous charts, Gamasutra's 'Game Design Essentials' series looks at the design lessons from titles in which 'the player must solve mysteries' - from finding secrets to wrestling with algorithmically generated content.

[Following three previous articles - for '20 Unusual Control Schemes', '20 Open World Games', and '20 Difficult Games', respectively, Gamasutra's 'Game Design Essentials' series looks at the design lessons from titles in which 'the player must solve mysteries' - from finding secrets to wrestling with algorithmically generated content.]

Not really all that very long ago, a game was released called The Legend of Zelda. For the time it was ground-breaking, but as often happens with games, many of the really interesting things about it were not copied in the inevitable onslaught of games it inspired in the following years.

One of those features was Zelda's huge variety of secret passages. While other games, including later Zeldas, will sometimes throw in a poorly-hidden secret chamber once in a while, the first Zelda did it all the time. Nearly half of its overworld screens, in fact, contain a special area of some type, offering rewards ranging from handfuls of rupees to entire dungeons that must be found to win the game.

The existence of so many things hidden in the game that don't have to be found lends the game a certain quality, one best described as verisimilitude. Verisimilitude is a useful word to use in describing video games. It means the quality of being like life, but the connotations are more profound than petty "realism," which has been redefined in the game review sphere as the quality of the graphics. Properly used, the word means that there seems like there is a world outside the borders of the screen, happening regardless of what the player does. It implies the existence of a fully-fleshed world, one that's more than a mere collection of polygons or tiles that might as well be sealed in Plexiglas. It allows a game to better enable the player to forget that it is, really, just a game.

Of course in games this is usually faked, although with varying degrees of success. Grand Theft Auto and Dead Rising, where one can tell the story to take a running jump and go off and explore on one's own, fake it pretty well. Games that force a strong, linear narrative on the player, not so well.

Not all games require that the player be immersed, and pretend to actually be a participant in the game world. Indeed, it's probable that too many games desire this state, and fail badly when they try. But there are other reasons for wanting to instill mysterious elements into a game. But I should define my terms. By saying "mysterious," I mean games that hide some aspect of their play or workings from the player. These are games in which the unraveling of hidden knowledge is essential to the game. These are games in which the player must solve mysteries -- thus the word "mysterious."

There are two major ways to do this. The most common is to include a lot of pre-made content the player must discover. This is, by far, the most common method, and nearly all games do this in one way or another. First-person shooters only reveal the portion of their territory which is visible to the player's camera. Even simple games like Pac-Man could be termed mysterious, in that the behavior of the monsters is algorithmic, but difficult to figure out during a game. All games are mysterious if the category is defined too broadly, so we will concern ourselves with games that go to unusual lengths, games that take the matter deeper than just the unveiling of new content:

The standard disclaimer: This is not intended to be a "top 20" list, and these games are not presented in a ranked order. Some of the games may seem to only be peripherally associated with the topic. That's because, to truly understand some concept, it's useful to look at both obvious and non-obvious cases. Most of these games are older, but this is as intended. Older is not the same as worse! The purpose of the article is to show how other games have done it over the years, and hopefully to inspire you in working on your own projects. You could even play them to see the principle in action.

Games That Emphasize Finding Secrets

1. Super Mario Bros. 3

The white blocks

Developed by Nintendo

Designed by Shigeru Miyamoto and Takashi Tezuka

Reason for inclusion:

In addition to the usual secrets that come just from being a Super Mario game, the third game in the series has some amazingly obscure things to find. If it weren't for Nintendo of America's own player's guides from the time we would probably have never found the Magic Note Blocks, treasure ships or white mushroom houses, let alone the special properties of white background blocks and how they could be utilized to find a Warp Whistle.

The game:

The Super Mario Bros. games make searching for secret power-ups and passages into a play mechanic itself, and SMB3 had probably the most deviously hidden ones of them all. Looking for invisible blocks has always been part of the Super Mario Bros. games, and there's an unavoidable aspect of trial and error to doing it. But for obscure secret areas, Super Mario Bros. 3 takes the proverbial cake.

It's well-known to fans of the game that some of the rectangular, decorative blocks, which can be stood upon as platforms, have special properties. They come in several colors, but only the white ones are in any way unusual. If the player stands on a white block for several seconds holding the control pad down, he will "fall behind" the block. The NES then uses a sprite priority feature to make Mario appear to be behind the background. The player will stay back there maybe eight seconds, invisible if he's standing by any of the background hills or such. There is no clue in the game that this will happen. It is pure mischievousness on the part of the designer.

This is pretty random by itself. While behind the scenery, the player passes by enemies, making him effectively invulnerable -- but since in all the levels of Super Mario Bros. 3 there only a handful of white blocks to be found, this function rarely enters into strategy. And yet, this secret function is required to obtain one of the game's three Warp Whistles.

Because doing it allows the player to warp ahead levels, its function is analogous to running at the top of the screen in the original Super Mario Bros. (ably discussed by Jeremy Penner in Gamer's Quarter #7.) But its significance is greater. By taking a nearly universally-ignored aspect of platform gaming, the color of a type of generic background element, and attaching significance to it, the designers imbued the whole game world with far more mystique than it would otherwise have. There is only one important white block in the game, found in the very first world, and no other random background element carries special significance; all the others are designed to be clearly read by the player, from pipes to note blocks to donut lifts.

Yet the white block trick implies that there is a lot more to the world than what is visible. It demonstrates mysterious properties that only an expert could know. It was knowledge of prime importance on early '90's school yards. It carries with it the whiff of magic. Thus, this one trick lends weight to the whole game. The fact that everyone knew the trick within months of the game's release doesn't prove it to be ineffective -- rather, it proves it worked. As Dr. Strangelove remarked, the whole point is lost if you keep it a secret.

Design lesson:

In a way, it's the ultimate dumb trick. There is really no way to know ducking for several seconds on a certain spot in 1-3 will lead to one of the game's most valuable treasures. But the hint is there, and the trick is known. And although it's only one trick in a game with many, it's obscure enough that it makes the player wonder about the entire rest of the game.


2. Bubble Bobble

Item generation mechanism, vast assortment of items, Bubble Alphabet, game modes and codes, and ending conditions

Published & developed by Taito

Designed by Fukio Mitsuji

Reason for inclusion:

How could this one not be included? Possibly the most mysterious game ever produced for arcades, with the only likely exception being its sequel, Rainbow Islands. Lots of stuff about this game was only fully understood when someone finally disassembled the code a few years back.

The game:

Bubble Bobble's multiple layers of secret knowledge make it a game for wizards. A huge array of arcane trivia must be learned to exploit Bubble Bobble's many systems. Some of it is only now becoming commonly known.

First thing to know is that the arcade game has secret codes. That was almost unheard of at the time -- yet Bubble Bobble not only has them, it will tell the player about them in the right circumstances, and using one is required to see the game's real ending. The circumstances in question, however, are nearly obscene: a game must be played to level 20, 30 or 50 without dying in order to see one, and death is rather common in Bubble Bobble after the first few levels. Once on the proper level, the bonus item normally generated in the level will instead be a door to a secret room, containing huge score bonuses and the code printed on the background... but the code, itself, is written in code.

At first it just looks like background decoration of runic glyphs, but it's really a secret message from the developers. The secret is spilled on the ending screen, where the player is informed "But it was not a true end!" and the specialness of the glyphs is revealed. That is, if he won in two-player mode. Winning with only a single player in the game sends him back to a random level. D'oh!

One of the secret codes makes the doors that lead to the bonus levels appear regardless of lives lost, which is nice to know once the player's already figured out the code, I guess. Another code, when entered from the title screen in the machine's attract mode, puts the game into "Super" mode, which mixes up the enemies in the levels and is somewhat more difficult. But it is only in Super mode that the game can truly be won, by working through all 100 levels again and finishing up in two-player mode. (And without dying, incidentally, but fortunately most people who win actually play as one player through most of the game, only putting player two in after the last boss has been beaten, and having just joined he won't have ever died.)

This is far from the only mysterious thing about the game. Probably the most mysterious is the formula that determines when special items appear. Most players believe it to be random, but actually they're all directly determined by the player's actions. The game maintains counts of a large array of trivia, like bubbles popped, times jumped, water bubbles burst, and times wrapped around the screen. When a counter exceeds a threshold value, a flag is set scheduling the item to be generated in an upcoming level.

The counts and flags are not reset when a game is finished, which is why new players often get treated to advanced items in the very first levels. But it also means if someone knows that, say, popping water bubbles makes level-skipping umbrellas appear more often, he can take advantage of that fact to skip ahead more often. Some of the tricks that make items appear cannot be done on every level, so it also tends to cause certain items to "clump," generating more often on particular boards.

It's nearly a textbook example of chaotic behavior in game design. The player's many varied actions lead, through unknown processes, to results that you'd assume are random, but seem to have some mysterious consistency to them. It is an interesting way to bring players into a game: to pin success on objects that appear almost on command, but without telling exactly what that command is.

Design lesson:

Pseudo-random numbers are used by many games, but Bubble Bobble, while apparently random, in fact contains few of them. Once their principles are understood they can be gamed, but they are not explained to the player. The result is that different play styles produce consistent variation in the game's response to them, which can provoke responses from players so complex that they border on superstition.


The Bubble Bobble mechanics discovered through source code examination are explicated at the Bubble Bobble Info Pages.


3. Rainbow Islands

Bubble Bobble with even more secrets

Developed by Taito

Designed by Fukio Mitsuji

Reason for inclusion:

The item generation scheme for this game isn't quite as complex, but it's still possible to make the items you need with some planning. Then there's the means players must undergo to obtain jewels, which must be collected in order to get the true ending. And then there's the super goals obtainable by getting the jewels in color order, and special permanent powerups for doing so! And then there's the secret levels! And then there's the secret ending for not dying! And so forth! Exclamation point!

The game:

While definitely a successor to the play of the first game, Rainbow Islands discards much of Bubble Bobble's item generation criteria. Instead, just killing a lot of enemies without dying will eventually produce the more useful power-ups. But it has even more secret areas and endings to find. It is probably the king of the Bubble Bobble play style because of it.

The basic mechanic of the game is to create rainbows, this game's analogue for the bubbles in the first game, and trap enemies beneath them. Then the player can jump on the rainbow, sending it crashing down and killing all the enemies beneath it -- sending them flying around in an arc before coming to rest on a platform. When multiple enemies are killed this way at once, they produce colored gemstones.

Levels can be finished three ways. The main way is to just go through and beat the boss, but if even one level is cleared that way, the player cannot get the best ending. It's really a trap, for although the enemies are the cause of lives lost, and spending a long time in a level also kills the player, the player can't just make progress normally and really win the game. He has to worry about other things along the way.

To really beat a level, one gem of each color must be obtained before the boss. Gems are generated by killing multiple enemies at once, but their colors seem random at first. Perhaps predictably, there is a trick to getting needed colors. When an enemy flies around after dying, the X-position of the place it comes to rest determines the color of gem that will appear there. The left edge of the screen is red, the next seventh of the screen over is orange, the next yellow, and so on through the spectrum, ending with violet at the right edge.

Each level has four stages, and the gems carry over from stage to stage. So to "super-clear" the whole level, the players must have gotten one gem from each vertical stripe of the screen in the stages leading up to the boss. Doing this causes the boss to reward him with a giant gem upon its death, and finishing the normal last level with all seven giant gems makes the real last levels available. (Cleverly, they're all based on other Taito properties like Arkanoid and Darius). Those levels have mirrors instead of gems, but they're obtained the same way. Getting all of them allows the player to win for really, really real... if he can beat the last boss, that is.

But there's more. If the players collected the gems in color order, from red to violet, then when the boss is reached, a special door will appear. Entering it skips the boss, rewards the player with his hard-earned diamond, and grants him a permanent power-up that lasts the rest of the game. This is all on top of the usual find-the-hidden-object gameplay shenanigans.

Design lesson:

Riddles and mysteries abound in this game. Secrets cannot make a game all by themselves, and Rainbow Islands' core play mechanic, while good, isn't quite as strong as Bubble Bobble's. Yet while both are long games even when played normally, no one who completed either game in the arcade and seen the Bad End could mistake that there was more left to do.


Perhaps the most complete resource on the game is the Rainbow Islands Info Pages.


4. Marble Madness (home computer versions)

The Water Maze

Developed by various developers working for Electronic Arts (original version by Atari Games)

Originally designed by Mark Cerny

Reason for inclusion:

It's not too well understood even now, but the computer versions of Marble Madness contain a secret level called the Water Maze. It's obscenely difficult and obscure to get through, but it's not obvious how to get to it, either.

The game:

It's not well-known (despite being featured in magazine ads), but the home computer editions of Marble Madness published by Electronic Arts contain a secret level of sorts. In the first level, if the player jumps off the pointed sides of the trench leading to the goal and lands on the floor on the left side of the screen, there's a secret passage to be found. It can't be located just by bumping around; he must wait on a specific spot until the timer reads 13 seconds remaining. Done correctly, an elevator will appear leading down, and soon after he'll be in a new area with 99 seconds on the clock. This area is the Water Maze, which appears only in EA's ports of the game.

The new area is a bit more fidgety than the real game. Instead of a series of action movement challenges, it is more a series of puzzles where the player must figure out what to do to move on. Many of the puzzles require two marbles to pull off, so while a single player will be let into the level, he won't really have a chance of completing it. Many of the puzzles involve elevators or rivers, objects which don't appear in the main game. The game rules are also different there, for if the clock runs out the level resets, but if the player dies the game ends immediately.

It greatly changes what it means to play Marble Madness, and it's maddeningly difficult besides, so it's fitting that it's relegated to an obscure easter egg in a dark corner of the game.

Design lesson:

The Water Maze plays differently than the main game, is fairly small, and finishing doesn't cause anything special to happen, so it's good that it's relegated to being a weird little secret. But that moment when a player happens upon it for the first time is really something.


5. Ogre Battle

Derandomized combat, obfuscation through complexity, character acquisition, and the Chaos Frame ending spoiling mechanism

Published and developed by Quest

Designed by Hiroshi Minagawa

Reason for inclusion:

This is a game that nearly everyone has to resort to a FAQ to play at some point. While the player is progressing through the game, the game is also keeping score in an obscure way. After finishing the last level, the score directly indicates which ending the player receives. But it's hard to keep the score up, and it's never explained exactly how it changes...

The game:

Ogre Battle is a game that's interesting for many reasons. It's a Japanese RPG that still takes a fairly simulationist approach to the play, and that's reason enough for examination all by itself. It's a decent challenge and has a strong strategic (as opposed to tactical) component, moves along in real time, and even has a strong economic component. But when a fight begins the player is largely left out of it. His characters decide for themselves what to do.

About those characters... They each have a stat called Alignment that maps generally to the D&D usage of the term: high alignment numbers, going up to 100, mean Lawful, and low alignment, down to 0, means Chaotic. The player will typically have many parties on the field at once, and each one has its own alignment value. Defeating darker enemies like vampires raises alignment, and lighter enemies like clerics lowers it. There are other things that modify alignment too, but once it gets close to its limits on either end of the scale it becomes more difficult to change it back. Character advancement often depends on alignment.

Now, there are other things to note here. When characters that are low in alignment take over one of the game's town bases, the game says the town is captured. If the same town is taken over by a high-alignment unit, the message says the town is liberated. These are very important messages, for the game also keeps track of another stat, this one describing the player. It is Reputation, and while character Alignment is an easy-to-read number, Reputation is never reported directly except through a very small bar. Here is a primary rule governing Reputation: capturing towns lowers it, while liberating them raises it!

A number of other things also affect Reputation, and tellingly, they do it in a way that makes the game more difficult if the player is trying to keep it high. Beating enemies with characters of much greater level than them (more than two levels difference) lowers reputation, while doing so with characters of less difference, or even of lower level, raises it. As game time passes on a given map, the player earns income from the towns he's taken over. Money carries over from map to map, but income resets. This might inspire some players to dally on a map and build funds, but hanging along too long lowers reputation.

So why is reputation important? Ah, that makes the game even more mysterious. In addition to characters joining up or not depending on player reputation (generally undocumented opportunities), reputation directly affects the ending the player receives after winning the game. A really low reputation will give the player a bad ending; in one, the player's character becomes a new tyrant who gets assassinated by one of the characters in his group.

Of course, none of this is explained to the player except in the manual, and there but vaguely.

Design lesson:

The player's actions throughout the game are put into an algorithmic blender, and at the end that value (among other things) selects the final outcome of the story. The result is that Ogre Battle is actually scored, just as much as Pac-Man or Rogue, but the player isn't told that score with any degree of fidelity. The N64 sequel takes this even further: the player doesn't even get that bar telling what his reputation score is.


GameFAQs has a nice mechanics FAQ on Ogre Battle that provides a more fleshed-out description of the Chaos Frame system.


6. Magic Sword

Many items, Bubble Bobble-like item functions, and surprisingly deep strategy

Published & developed by Capcom

Designed by Y. Ohnishi, T. Sadamoto and Y. Okamoto.

Reason for inclusion:

Sorta like Bubble Bobble with barbarians, a hack-and-slash platformer with a lot more personality and depth than it has any right having.

The game:

Magic Sword is an inexplicably awesome little arcade game. It's a fantasy hack-and-slash that doesn't take itself too seriously, and feels more like a relative of stuff like Pang and Rainbow Islands than contemporary Capcom fantasy games King of Dragons and Knights of the Round.

Those two games are actually brawlers, more like Final Fight than D&D. Magic Sword manages to feel more genuinely adventurous because, mostly, of the wide variety of secret things to find. The game's "helper" character system plays a role here. Helpers are assistant characters who follow the player and generally copy his movements. They work a bit like options in Gradius, but the player can only have one at a time, and they can take damage. As the player makes it through the tower's 50 levels, he encounters various doors with different kinds of locks on them. Opening a door uses up a key but makes available the contents -- usually a helper and a item. There's actually not a key shortage per se, and the early levels give the player an essentially infinite supply of each type (but finishing a level with extra keys is worth more points, and more bonus health).

The keys add an element of resource management to the search for treasure. Most of the doors are plainly visible, but opening all of them costs the player a key if he has one to spare. Inside there are a variety of items and helpers, but the player doesn't know what unless he's memorized them on previous playthroughs. (Some even contain enemies.) The helpers have different strengths that make them better suited for some areas than others: some have powerful melee attacks, some fast distance attacks, some magic that's strong against undead enemies, and one, the Thief, locates hidden objects for the player. A couple helpers are themselves secret, appearing only in a few places or from special means, and are fairly high-caliber discoverables for this kind of game.

The thing that makes the secrets in Magic Sword particularly impressive is the amount of coding that went into them. The helpers each have their own subroutines and effects upon the game for finding them. The big tradeoff for including truly secret secrets in games is: why waste manpower including content that will only be seen by a small percentage of players?

One reason is that it randomizes the game. If players can't always find a useful object because he doesn't know what makes it show up, or doesn't even know it exists, it increases the diversity of experience, and ultimately makes the game more replayable. Different players end up facing different challenges. Beating a boss with a Lizardman is easier than with a Thief, but the Thief will show hidden chests that may provide their own advantages, which could be just a useful in the boss fight.

Another reason is that it makes the game feel more mysterious. Most games these days are laid out on a linear track without opportunity for meaningful deviation. Deviation could come from providing alternate territory to explore, like in Mario games, or it could come from varying the resources available to the player.

Design lesson:

Although the enemy and item positions are generally hard-coded, there's enough randomness in Magic Sword, enough changes to the game situation made possible by whatever helper or item he has, that in practice it's really quite replayable. This way, the implications of the pre-made levels vary according to the player's helper and carried item, where the player can only have one of either of those things at a time. It's a style of game design that's relatively uncommon anymore, yet can greatly extend playability if done well.


7. Athena

Block-breaking, many items and functions and lots of secrets.

Developed by SNK

Reason for inclusion:

The game plays like a successor to Super Mario Bros. because of the huge number of breakable blocks that hide treasures inside them. Shattering them is key to success, but there are lots of weapons to choose from, and some of the best for killing enemies are bad for breaking blocks.

The game:

Lots of people are down on Athena on the strength of its horrible NES port, which is loaded with bugs, spotty controls and a brutal damage model that can kill a full-health player in a moment. The arcade game is rather more polished, alth

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