Puzzles and problem solving

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26 January 2006

by Mike Rozak

I decided that I need to understand puzzles and problems solving more, since they significantly affect sub-games, which in turn, affect quest design. This article is the result...

To put it simply, every puzzle (or problem to solve) has some aspect(s) that makes it difficult or challenging to "solve". I was originally going to produce a list of puzzle categories, but realised that the categories can themselves be categorised into "what's the difficult part is", so I expanded my mission.

This article doesn't deal with the appearance/dressing of the puzzle, just what makes it challenging. Whether the puzzle is presented by a machine, NPC, riddle, or natural occurrence is irrelevant to this discussion.

My list of puzzle categories and the categories' categorisations follow:

• Puzzles where the challenge is to find or identify the puzzle, "Is this a puzzle to be solved?":
  
  
  • Disguised - The "jewel encrusted egg" from Zork appears to be a treasure, and it is. However, it's also a puzzle. Normally, I'd say that such puzzles are poor design because the player has no way of knowing they're a puzzle. In the case of the jewel encrusted egg, there is a hint (see below) that it's a puzzle, and not solving the puzzle doesn't significantly affect the game, although you do lose a few points.
    
    
  • Guess the NPC-conversation keyword - If a player happens to mention the right phrase to a NPC, the NPC initiates the puzzle. This is poor design, since how does the player know what they should speak in the first place?
    
    
  • Pixel hunts - The puzzle isn't easily seen. Only by moving the mouse slowly over the entire screen will the "pixel" be found that the user can click, which then initiates the puzzle. Pixel hunts can also be used to make actions difficult (see below). These puzzles are usually frowned upon.
    
    
• Puzzles where the challenge is to to know what to do, "How do I know what I'm supposed to do?":
  
  
  • Obfuscation - Eye candy can be used to hide what's actually going on in the puzzle by providing animations and sound effects that confuse the brain about the underlying puzzle "structure". For example: At university, someone played a party game where he would arrange sets of forks and knives to represent a number. He kept repeating the process with different numbers. The more astute observers quickly exclaimed, "Ah!," chuckled, and stated the correct number. I didn't figure it out; he was using the cutlery as a diversion and subtly placing his hands on the table afterwards, revealing the actual value by the number of fingers he exposed.
    
    
  • Codes - Many codes can be cracked without external hints, although they take time. For example: If a player knows (or assumes - which is perhaps the important point) that a certain word appears in code they can begin to guess the rules of the code. This helps them learn more rules about the code, which in turn reveals yet more. You might also categorise this as experimentation, even though the experimentation is with a hypothetical decoding machine that the player, not the author, has created.
    
    
  • Gestalt - The solution to specific puzzles becomes apparent when the player understands/perceives "the big picture". This category comes from Bob Bates, who describes a puzzle in Brian Moriarty's Trinity: The player is transported to a bizarre world. As they explore, they gradually realise they're wandering around the face of a sundial they had seen previously. The puzzle cannot be solved without this understanding.
    
    
  • Lateral thinking - The solution is not obvious, or the obvious solution is not possible/allowed. For example: One of Aesop's fables describes a raven landing on the rim of jar of water. It wants a drink but it can't reach down to the water level. The solution is to gradually fill the jar with small pebbles until the water level rises.
    
    
    • Riddle - Riddles (in my limited experience) are about lateral thinking.
      
      
  • Research - The only way to know how to solve the puzzle is to research a solution, either inside or outside the world.
    
    
    • Clues, hidden - The puzzle's solution can only be discovered by looking for hidden clues scattered throughout the world. These clues are usually in the form of notes, scribblings on walls, etc. The trick is knowing which scribblings are red herrings and which are valid clues, as well as how the clues can be applied, which is a combination of research and obfuscation.
      
      
    • Clues, obvious - Some worlds have the solutions to puzzles clearly written in far-away rooms. The only challenge is to keep copious notes on all potential clues or their locations so clues are available when they're needed, turning them into part research and part preparation.
      
      
      • Codes - Coded messages are often decoded by finding the clues about the code.
        
        
    • Experimentation - Players encounter a machine presenting several buttons and knobs. They are allowed to play around with the buttons and knobs to figure out how they affect the machine or its output. Once players know the effects, they must determine how the buttons/knobs should be set in order to produce a desired outcome, a logic puzzle. The Hitchhiker's Guide babble-fish puzzle is another example of experimentation. Experimentation is (distantly?) related to Gestalt.
      
      
    • External knowledge - If a player knows Latin, they can read the an inscription on a tombstone. If they don't, the need to find a Latin dictionary on the Internet.
      
      
    • Game cheats - If your puzzle needs a game cheat to be solved, then it may be too difficult.
      
      
    • Observing over time - Sitting back and watching a NPC (or machinery) go through a routine provides the solution.
      
      
• Puzzles where the challenge is preparation:
  
  
  • Key and lock puzzles - Somewhere in the world is a locked door. Elsewhere is a key that unlocks the door. The solution to the puzzle is to pick up every key in sight and carry it around until the appropriate door is found. Keys do not always look like actual keys, and doors are not always actual doors. This puzzle category is frowned upon.
    
    
    • Buttons far away from doors - A button is randomly placed in the world. Pressing it opens a door located far away. The solution is to press every button you see.
      
      
    • Buttons next to doors - A trivial "key and lock" puzzle is to have a button right next to the door that it opens. The only advantage is that the button alerts players that something bad might happen when they press the button to open the door.
      
      
  • Resource management - Inventory, skill-point allocation, etc. are about resource allocation. The player must plan ahead and figure out what items or skills would be wise to invest in. I'm not sure if this is a legitimate puzzle category, since players need clues/experience (above) indicating how resources should be allocated. Since some players inevitably misallocate resources, there must be a way for players to undo their poor allocation, usually with a tedium penalty. Zork, for example, used the flashlight as a resource to allocate, but didn't allow the a dead flashlight to be recharged, which isn't acceptable design today.
    
    
• Puzzles where the challenge is in the action:
  
  
  • Chance - There's a probability that even the correct actions might fail. A failure could require the player to redo some work (tedium), or just confuse the player as to whether they are performing the correct actions (obfuscation).
    
    
  • Difficult human tricks - These puzzles rely on actions that employ parts of the brain that don't work as well as we'd like:
    
    
    • 3D/4D spatial puzzles - The human brain can't quite understand some complex spatial problems, making the the actions required to solve problems difficult.
      
      
      • Mazes - Some mazes are difficult because of the spatial issues.
        
        
    • Audio/music - Most people don't have perfect pitch, and can't remember any more than a few notes.
      
      
    • Colour matching - Humans aren't very good at exact colour matching. While players can't take notes, they can use Alt-PrintScreen to solve a colour matching puzzle.
      
      
    • Logic puzzles - The rules of the puzzle are known. There are too many permutations to try all combinations though. The player must use logic and the process of elimination to determine the right inputs to the puzzle.
      
      
    • Mathematical - Many mathematical calculations are difficult (for most people).
      
      
    • Memory - Puzzles that test the limits of people's memory are possible candidates. Unfortunately, these don't work too well in practice because players take notes on paper.
      
      
    • Reading emotions - The way to win at poker is to read your opponent's expressions.
      
      
    • Pattern recognition - Humans are good at recognizing some patterns (like faces), but others patterns are trickier to perceive.
      
      
      • Jigsaw puzzles - Lots of tiny shapes that need to be fit together. Jigsaws are a combination of pattern recognition and tedium.
        
        
    • Time limits - Trying to complete a series of actions in a fixed amount of time makes them more difficult.
      
      
    • Twitch/dexterity - First-person shooters rely on this.
      
      
    • Understanding the mind of the enemy - The way to win at chess is to understand what your opponent is thinking and planning, and this is no easy task.
      
      
    • Visual noise - Distractions (such as eye candy) can make it difficult to act. For example: A character might get knocked on the head, have blurry/spinning vision, and still need to complete simple tasks.
      
      
  • Guess the verb - A player knows what they want to do, but can't figure out how to phrase the command so the interpreter understands. Guess-the-verb "puzzles" are not usually designed to be puzzles, but are accidents of implementation.
    
    
    • Pixel hunts - The player knows that press a button that looks like a leaf to open a door. This isn't easy since the door-leaf is hidden amongst thousands of real leaves. Unfortunately, pixel hunts are often intentional.
      
      
  • Social - This only works in multiplayer worlds. The solution is to convince other players to help solve the puzzle. Convincing another player introduces a variety of challenges, not of the game's making though. For example: A door that opens only when two buttons in separate rooms are pressed simultaneously.
    
    
  • Time sync (tedium) - Time syncs just take a lot of time to complete. They're not particularly fun. Adventure games (theoretically) avoid these "puzzles", but CRPGs and MMORPGs often include them.
    
    
    • Combinations - The solution to the puzzle is easy to understand, but difficult to implement: Just try all possible permutations/combinations. A variant includes trying to all possible permutations of "combine item A with item B" and "use item A on item B". Not a good puzzle.
      
      
    • Maze (tedious) - Players know the process for getting through the maze; they must tediously map it. Some mazes require clever solutions instead of tedium. Tedious mazes are cliche and frowned upon.
      
      
• Puzzles where the challenge is to learn:
  
  
  • Game (mastery) - A "puzzle" of this category will be encountered many times throughout the game, but in slightly different guises. The puzzle's difficulty increases each time it is encountered, counteracted by the player's mastery of the game, learned from previous encounters. Often, players know the generalities of the rules, but not the exact details. CRPG combat uses this sort of "puzzle".
    
    
    • Twitch/dexterity - This is included both here and under challenging actions, since hand-eye coordination must be learned for players to succeed at most twitch games.
      
      
  • Play a musical instrument - I thought I'd throw this one in to demonstrate an alternate learning challenge. I've never seen it in an adventure game though.

I'm not entirely happy with these categories. They don't seem orthogonal enough to me. However, they're a start. I'll put this on the Internet and perhaps come back to it in a few months.

PS - While I wrote down many of these puzzle categories from my own gaming experience, some of them came from conversations, archived and contemporary, on rec.arts.int-fiction, listed in ifwiki.com.