Thursday, September 27, 2007

Game Design Questions

Some questions every game designer should ask during the game development process:
  • Are the game's interfaces and user controls consistent throughout the game? If they're not, is there a good reason why they shouldn't be consistent? Do the inconsistencies make logical sense?
  • Do the controls adhere to known conventions for the game's genre? If not, in what ways is the game's control scheme superior to that of its predecessors?
  • Are there objects in the game that behave contrary to reasonable player expectations? Are there objects that look like they should do something they don't do? Are there objects that do things that are not suggested by their form?
  • Does the player feel lost ("where am I" / "what am I supposed to do next") when I don't intend him to feel that way? If I do intend it, do I have a very good reason for it? Does my approach convey the desired emotions, or is it merely frustrating?
  • Does the game provide sufficient cues for the player to anticipate danger? If there's any surprises, am I giving the player a fair chance to react to them?
  • Is the game's failure response (e.g., whatever happens once the player's avatar dies) tied to the game's save system? Wouldn't it work better if the two were uncoupled?
  • If the game features cutscenes or other narrative elements at the beginning of the game, how long does the player have to wait until he gains control of his character? What about other cutscenes in the game?
  • If players skip a cutscene or forget some important detail, can they watch it again?
  • If the game does not allow players to skip particular cutscenes, do I have a good reason for it? Why not just let players skip and replay these cutscenes at will?
  • If there's an in-game tutorial, does it interfere with the player's sense of free will? Does he feel he's being played like a puppet, or otherwise constrained?

Saturday, September 01, 2007

Design Flaw: In Your Face

The Game: In Your Face

The background: In Your Face is a street basketball game for the original Nintendo Game Boy. At the beginning of every game, a coin-flip animation is shown to represent the practice of flipping a coin to determine which side gets control of the ball.

The problem: The coin-flip animation is purely cosmetic, for the human player always gets initial control of the ball. The virtual coin's behavior does not agree with the player's expectation that a coin flip should produce random outcomes, thus the game's implicit promise to the player is broken.

The solution: Allow the coin flip to determine who gets control of the ball, or else get rid of the coin flip animation.

Sunday, August 26, 2007

Bad Interface: Civilization IV

The game: Civilization IV

The background: Numerous times over the course of the game the player is asked to choose from a list technologies that determine the units and improvements available in play. Certain items on each list are emphasized through the addition of the word "recommended" right next to those items.

The problem:
The placement of the word "recommended" next to particular items introduces a bias toward those items. This is fine for new players, but for slightly more experienced players the game's recommendations can become an obstacle to uninhibited choice. After all, if the player thinks the game has selected the best of all the available choices, why should he pick anything different? This kind of player lacks the experience necessary to make the best choices on his own, and the game's interface hinders the player's acquisition of such experience by interfering with the free exploration of the game's technology tree.

The solution: One way to solve this problem is to separate the game's recommendations from the main technology selection interface, through the use of a second-level advisory interface. If that is not desired, another approach is to limit the use of such hints to the easiest difficulty levels, avoiding their use at higher difficulties.

Tuesday, August 07, 2007

Design Flaw: Zelda: The Wind Waker

The game: Zelda: The Wind Waker

The background: One of the islands in the game, the largest of the Mother and Child Isles, is impossible to reach on foot. A talking fish that's swimming in the area tells the player he may reach the island by taking "a ride on a whirlwind":
"They say that inside the ring of rock that makes up the perimeter of that island, there lives an incredibly beautiful fairy! But the thing is, nobody's ever met her. Supposedly, the only way you'll ever meet her is to take a ride on a whilrwind and drop inside that rock perimeter from the sky above. Doesn't sound easy, fry..."

The problem:
The fish's suggestion is potentially misleading. In certain areas of the game world the player can use his Deku Leaf to glide over cyclones and be lifted high up in the air, extending his gliding range. Recalling these experiences, some players will improperly deduce they're supposed to ride the small cyclone that's found in the immediate vicinity of the Mother and Child Isles.

In fact, the only way to reach the island is to play The Ballad of Gales, which players can learn by defeating Cyclos, the wind deity, using Link's bow and arrow. A player who has yet to learn The Ballad of Gales1 is unlikely to realize it's the only way to get to the island.

The solution: One way to solve this problem is to allow the player to enter the island using only his Deku Leaf. This approach is consistent with what the player already knows about the game's mechanics, and is therefore consistent with his expectations.

If that approach is not desired, a different way to solve the problem is to get rid of the small cyclone that's swirling in the vicinity of the Mother and Child Isles. This would eliminate the primary source of confusion: the presence of a cyclone that cannot be used to get into the island.

Finally, if for some reason the cyclone should not be removed, the fish's message should be modified to make it unambiguously clear that entering the island requires something more than just a Deku Leaf.


Footnotes:
  1. The only clue to defeating Cyclos is provided by the fish near Shark Island:

    "Tell me, small fry, have you ever been caught in one of those cyclones? The wind deity, Cyclos, uses those cyclones to fly across the sea instantaneously, or so I've heard. Could be just a rumor. Boy, if you had that power, you wouldn't have to spend so much time sailing back and forth across the sea all the time. Wouldn't that be nice, fry? But let me tell you, there's no way he'll give up his power easily! You can't get near the guy, so you'll have to figure out how to shoot him from a distance. Don't you have a weapon that can pierce things from a distance? You know, fffwip? FFFWIP, I tell you! You get my point, fry?!"

Remembering Goals

The issue: Certain kinds of games require that players keep one or more specific goals in mind as they play. Players who return to a game after a long absence may find it difficult to remember what they're supposed to do next, which may impede their progress.

Resolution: Provide some sort of reminder of the player's unfinished tasks. This may assume such different forms as a list of pending and completed goals (Psychonauts), an in-character reminder of pending goals (Dragon Quest VIII), or a video log of significant cutscenes (Ratchet and Clank: Going Commando). If any of the tasks require knowledge of specific details previously revealed in play, the player should likewise be reminded of those details.

Sunday, August 05, 2007

Bad Interface: Dragon Quest VIII

The game: Dragon Quest VIII

The background: In a battle against a group of monsters, a player who wishes to attack has to first choose the "attack" option from within the game's "fight" menu, and then pick whichever monster is the player's intended target.

The problem: Once the player has defeated every monster except for the last one, the game no longer waits for the player to pick a target. The reason that's a problem is that the player, having become accustomed to performing two actions for each attack, is now required to adapt to a different mode of operation where each attack requires only a single action. A player who presses twice on the action button while expecting a single attack will be surprised to find out that he's actually chosen to attack twice (once for each player character).

The solution: Have a consistent interface that requires the player to always pick a target for his attacks. Avoiding inconsistencies is more important than saving the player a single button press. Consistency favors the natural tendency for routine behaviors to become automatic, and avoids player confusion.

Thursday, April 19, 2007

Divide Progress Into Discrete Units

Defeating an enemy; overcoming an obstacle; surviving in the face of adversity: success and failure are at the very core of the game-player's experience. Games offer players a number of choices, some of which lead to success and some of which lead to failure or non-success. Together with the challenges presented to the player, the fact that the player might fail lends significance to the player's choices and actions. Although failure can be a negative experience, it is also the very thing that makes success meaningful.

There are two kinds of failure in games. One kind of failure concerns the player's inability to satisfy a particular success condition that nevertheless remains satisfiable, and another kind of failure takes place whenever the player encounters a particular failure condition. While the first kind of failure is simply a failure to succeed, the latter kind calls for a particular response to the player's actions.

The manner in which a game responds to player failure is essential to its design. A game designer can promote player tension and create a sense of danger through challenging gameplay and the careful use of failure conditions and responses. When a failure condition is met the game will respond by penalizing the player in some fashion, often through the loss of progress. Thus, the player might be forced to replay certain parts of the game or be presented with an extended challenge as a penalty.

Progress is defined as the act of moving forward toward a goal. That goal may be a physical location within the game's environment, or it may instead assume the form of a desired outcome tied to the successful performance of a particular task or the conclusion of a series of steps in the proper order. The player's choices determine whether progress is made or lost.

Many games divide progress into discrete units or milestones, where meeting a particular goal ensures that the player will not be set back any further than the current point in the game. When the player is placed in a situation that may lead to repetition or additional work upon failure, progress is said to be at risk. Once the player attains the goal at hand for the given situation, progress is said to be safe. All else being equal, the greater the separation between the two states, the greater the penalty for failure. A reasonable penalty can make the game more challenging and exciting, but too large a penalty will lead to player frustration. It is the game designer's job to achieve the proper balance between creating tension and avoiding player frustration.

Of course, it doesn't always make sense to divide a game into discrete units. Some designs call for continuous gameplay rather than division into discrete units of play. Games like Tetris and Sim City don't revolve so much around individual goals but are instead framed in terms of broad, overarching goals such as keeping the screen clear of blocks or maintaining a thriving city. Furthermore, games without failure conditions such as many nonlinear adventure games do not afford division of progress given that progress can never be lost. Nevertheless, there are many kinds of games that benefit from being divided into discrete units of play.

It is worthwhile to look at some examples of games that divide progress into discrete units. Some of the best games ever created employ this type of structure as the means of achieving a balance between the desire to make a challenging game and the need to make it manageable.

In Super Mario World the game is divided into stages. Dying at any point before the end of each stage requires the player to start over from the beginning of the stage, or from the middle of the stage if the player has broken the tape at the midway gate. Once the player has completed a particular stage he is taken to the map screen and is free to proceed to the stage that follows. Stages are connected together through the map screen, but each stage is also a self-contained unit.

In Zelda: A Link to the Past, the game is divided into dungeons or similar structures. In one particular case a yellow worm named Moldorm is able to push the player off the edge of its platform and down through a number of holes in the floors of the tower where it lives, forcing the player to climb back up to the platform whenever he's pushed off the edge. In this case, Moldorm's tower acts like a self-contained unit that is further divided into a number of floors, so that being pushed off the edge will keep the game within the confines of Moldorm's tower.

In Ratchet and Clank: Going Commando, the game is divided into stages in the form of planets that Ratchet and Clank must visit according to the mission at hand. Each planet is in turn divided into smaller sections according to a series of continue points. Whenever the player reaches a continue point his progress is saved against failure so the player is returned to this point whenever he dies.

In each of these cases, the penalty for failure is well-defined. The difference between the moment when progress is first at risk and the moment when progress is safe is explicitly designed into the game. As a known quantity, the designer has greater control over the game's difficulty than if this quantity were allowed to vary arbitrarily according to the player's choices. The game designer is able to choose the size of each unit of play, allowing the designer to fix the size of the unit and adjust the unit's difficulty by tweaking the individual challenges, or to fix the difficulty of each challenge and adjust the size of the unit to add new challenges and therefore manage the unit's overall difficulty. These two strategies are complementary and may be employed in alternating fashion for the greatest control over each unit's difficulty.

Not all game designers appreciate the value of these strategies. Some designers prefer to rely on a game's save mechanism to determine what happens once a failure condition is encountered. Since failure sets the player back to the latest save game, the player is able to manipulate the difference between the moment when progress is at risk and the moment when progress is safe. Some designers consider this to be a fair advantage insofar as the player is able adjust the game's challenge according to his abilities, but it also carries the disadvantage that it may lead players to adopt a strategy of minimal risk. In the worst case the player will save the game whenever there's an imminent threat and reload whenever he suffers any harm.

Allowing the player to minimize risk in this manner not only makes the game less challenging for some players, it also encourages sloppy design. The designer, lacking information about the size of the chosen unit of play, surrenders an important baseline upon which to judge the game's difficulty. The player, who is not familiar with the game's design, will tend to save whenever he feels uncomfortable with the amount of progress that remains at risk. Thus, if the designer assumes that the player will save at every opportunity, the result will be a game that favors or perhaps even demands frequent saving. The designer will have to make individual challenges more difficult in order to account for the expected saving pattern and may end up neglecting the overall play experience. If, on the other hand, the designer assumes that the player will save only occasionally, the result will be a game that buckles under frequent saving. While players could certainly choose to save less frequently in order to make the game more challenging, this assumes that the player is willing to play through parts of the game he has already faced and overcome when he could easily avoid them by saving the game.

One way to see how tying progress to the save mechanism can interfere with a carefully balanced game is to play such a game in an emulator, relying on the emulator's state-saving feature as the only mechanism for recovering from player failure. Even if it's convenient to be able to quit and resume the game at any point, it's a mistake to rely on a game's save mechanism as the way to protect progress against player failure. Whatever form a game's save mechanism may assume, it should not be a part of the game's response to player failure.

Further reading:
  1. Rules of Play discusses goals on pages 259, 251 and 342 - 344, and discusses victory and failure conditions on pages 259 and 261.
  2. In opposition to the ideas expressed in this article, Ernest Adams argues in favor of allowing players to save whenever they want to in "Bad Game Designer, No Twinkie! II", "Bad Game Designer, No Twinkie IV", "What Kind of Game Designer Are You?", and "The Bill of Players' Rights". Also, in "Difficult Questions About Videogames: How Can You Tell if a Videogame is Rubbish?" he's credited with the statement that "Any game that does not allow the player to save his or her progress, on a gameplay device equipped with a save mechanism, at the player's own convenience and at any time of the player's choosing, is rubbish."