Some Thoughts on Computer Game Design ========================================= I've been thinking about what it is about my favorite games that I like...I've thought about Game Design on and off over the years, and have begun to pull some things together for myself. Here's a start of a breakdown...feel free to add upon it and respond to individual ideas...I'd like to quote different reactions to these ideas in a non-profit hypermedia project I'm working on at school, and thought the life of these groups would have much to add. Dave Seah (dis6218@ultb.isc.rit.edu, pccdaves@aol.com) --- cut here --- The Player Why do we play games? We like challenges, and we derive pleasure when we overcome them. Games provide a safe context in which we can express our fantasies and dreams. We achieve a sense of stature and accomplishment by engaging in stimulating gameplay. Computer games are no different in the way they provide challenge and stimulation. As game designers, though, we are responsible for designing every part of every interaction within the self-contained computer world. The player has to be able to find and overcome the challenges we design into a game without feeling unfairly constrained or manipulated. For games in which the player plays an active role in a simulated social environment, emphasize the hero qualities of the character. By controlling the character throughout the game, the player establishes an alter ego. That joystick-controlled blip on the screen is the player, for all intents and purposes. The game environment becomes the world, and the player is the protagonist, with the potential to become a hero. Heros are always above average in their abilities, for it enables them to go forth and kick-ass in a definitive manner. The protagonist must undertake some form of the hero's journey. This can take the form of a developmental cycle, as it is in role playing games (RPGs.) A new character in the Ultima series, for example, starts out as a naked stripling, equipped with the wimpiest of weapons and armor. The character grows in experience by exploring the world, slaying monsters and engaging in quests. Eventually, the protagonist achieves a level of ability that is truly epic. The player experiences a vicarious sense of accomplishment through the actions and ultimate success of his/her character. In games that emphasize manual dexterity, the hero's journey is externalized. In an arcade game, the player usually controls some kind of ship. The ship itself may already be imbued with awesome weaponry and abilities; by surviving and wreaking destruction on the computer world, the player is shown to be a hero (or at least skilled) to his or her peers. A good example is the original version of Wing Commander. In this game, a chalkboard kept track of how many enemy kills were attributed to the player's character. It lists the game's non-player characters (NPCs) ranks as well, and the player could see how well he is doing as the story progresses. As the player grows more experienced, he moves up in the ratings. The chalkboard also makes it possible for players to compare their skills with their friends. "I fragged 105 furballs before I finished the game" was a common boast on the computer networks. In Wing Commander II, the chalkboard was moved to a less prominent area, and the emphasis was placed on the wooden story line, drawing the player into a simulated social environment. Game Environment As the player establishes and sets goals in the context of the game, the game must respond in kind by providing some kind of feedback. Without feedback, the player will feel lost and impotent, trapped inside an artificial world instead of participating in it. The interactive gaming experience must support the actions of the player, not thwart them. To maintain the illusion of a functioning, living world, the game designer has to ensure that there is some minimum interaction between the player's character and the simulated environment. As an example, the Super Nintendo version of Zelda provides lots of audio-visual feedback. As the player's character walks through tall grass, a rustling sound is heard, and the character's body below the waist is swallowed up. When walking in a shady forest, shadows fall across both the ground and the character. NPCs on the screen react to the presence of the player in a variety of ways or not at all. The player is drawn into the game because the game environment interacts with his/her character. The high level of interaction between player character and game environment is enjoyable in itself. The player should also receive some kind of feedback on his/her progress. In arcade games, this is accomplished with some kind of indicator (score, level, etc). The player ideally feels that he or she is in control at least most of the time. All hell may be breaking loose, but the player should know how much that is affecting his/her character. The rule of thumb is that for every action, there should be some kind of feedback or reaction. The game universe should have well-established conventions of how things work -- its own "law of physics." If the laws change, there must be a rational explanation. Arbitrary changes, especially those that impact the player's character, can have a negative impact on the gaming experience. Premise and Player's Expectations The player must know what to expect from the game world, journey or no journey. Usually, some rudimentary explanation is given to explain the game world. Ignoring purely abstract games like Go or Checkers, the game designer must establish both premise (story) and setting. The premise helps establish an initial motivation for why the game is the way it is, and the setting helps establish the tone. This can take rather trivial forms, but if the scope of the story matches the scope of the game, then I have no argument against it. By "scope of the game", I mean the range of possible associations and interactions. A complex political thriller as the story and setting for a straight shoot-em-up arcade game doesn't carry much credibility. Likewise, a game that is based on a popular movie is asking for trouble. People will carry their memories of the movie over to their expectations of the game, and are setting themselves up for disapointment. For the designer's expectations of the game, it is important to set the challenge clearly. You know what kind of experience you want to deliver, so make that clear right up front when establishing the story and setting. The premise (or premises) of the game will vary wildly. If a game is intended to be a visually confusing, surreal exploration of the inner mind, then let it be said up front. If the game is intended to be an accurate, uncompromising World War II simulation of the Battle of the Bulge, then different expectations are set. The designer must set these guidelines explicitly, and adhere to them. The game experience should fully support the premise and the player's expectations. Consider two space gaming genres: the side-scrolling "shoot-em-up" (or shooter) and the space combat simulator. In a classic shooter like Defender, the premise is pretty simple: Destroy all the waves of attacking aliens and protect your people. The gameplay is simple to understand, though the game itself requires superb eye-hand coordination of a level that is seldom seen today. For the gamer, the premise is secondary to the nerve-racking adrenaline rush of playing which is the main reason for playing. As a more recent example, the space combat simulator X-Wing is based on the Star Wars universe. Since it is based on the popular movie, players expect a lot from the game. The premise is that you are a rookie joining the Rebel Alliance. Although you can jump right into the missions and just start blasting TIE fighters, you are encouraged to go through the training process. Animated sequences and accurate portrayal of the Star Wars universe build the framework in which you play the game, and an included novella sets the tone for your tour of duty: You are a new recruit, and the Alliance is being ruthlessly hunted down by the Imperial fleet. You are not just flying any old spacecraft...you are flying an X-wing, escorting a crucial shipment of grain through dangerous Imperial patrols! There is a sense of an expanded game universe that exists outside the confines of the game, carefully reinforced with information from the mission briefing screens, but the story isn't stated overtly. You are not Luke Skywalker, but you know that he's out there somewhere fighting the same cause. Balancing of Goals From the initial motivation, the player can form (or be informed of) several long-term goals. The default goal is to win the game. Other long term goals may be to "find the Golden Sword" or "Return Peace to the Land." Players will formulate a number of short-term goals along the way. "To find the Golden Sword, I have to talk to everyone," or "To return peace to the land, I need to collect the Peace Crystals." Shorter term goals might be, "To get to the next level, I have to blow up all these ships," or "I have to find the Power Booster if I want to survive!" Some short-term goals are standing goals. These goals are always on the player's mind, as they continually contribute to the well-being of the character. For example, "I better not get hit by enemy blaster fire, or I'll lose a ship." The game designer manages the difficulty of these goals, and the player juggles them. For flexibility, I like to allow flexible goal completion. In other words, I like to allow some leeway in the order that goals are brought to completion. There is no single order that guarantees success. Putting together a structure that allows this is not trivial, and it depends on the kind of game. To take an old example, consider the classic Apple II game, "Castle Wolfenstein." The object (long term goal) of the game is to escape from a Nazi castle during WWII, initially armed with nothing but a pistol. Finding the "War Plans" was a secondary long-term objective. Since the game begins with the player trapped in a guarded room, clad in bright purple prisoner duds, the short term goal is to get out of the room without getting captured or shot. As the player moves from room to room, the standing goals are finding uniforms, keeping stocked with ammunition, and keeping the SS from getting on your tail. Balance short term with long term goals. You want short term goals, punctuated by moments of sheer terror. This is part of the "hero building" process. The short term goals should be immediate and compelling. This can be something as simple as "blow up more bad guys." Long term goals should be what drives the short term goals, giving them purpose and meaning. Not all games need purpose and meaning. DOOM is a good example: the gameplay is so compelling that you have no time to think about any long-term goals other than, "survive." It is the most absorbing game of its kind on any platform, in my opinion. Another aspect of goal-setting that I like is the idea of open play. In the case of Castle Wolfenstein, the goal of the game is to escape with the war plans. However, the player can take as long as he/she wants. In fact, the player can choose to use the game as an open play environment, effectively creating a new game. A common game was "Nazi hunting", in which players would just run around shooting everyone. Other players would try to get out of the castle as quickly as possible, ignoring all other aspects of the game. Castle Wolfenstein did not punish the player, because its structure was open enough to contain these kind of alternate games. Gameplay Part of the pleasure in a game comes from interacting with it. I enjoy controlling characters on the screen, making them solve problems or overcome challenges. I also derive satisfaction at overcoming those challenges with skill and dexterity. I set a limited goal ("solve the puzzle") and then I reach it ("puzzle solved.") The player should be able to do any action that seems reasonable, given the premise of the game and the goals formed based on those premises. If there is a situation in which the natural response would be to run like hell, then the character should be able to do just that. There should be a counter or defense for every move. If you are shot at, you should be able to move out of the way. If attacked, you should be able to counter-attack, or at the very least be allowed to escape. In the event that the player has just made some horrible tactical mistake, this should be made very clear so the player knows that it was "his fault." There should also be the knowledge that, "there is another way." The player will also want some way to gain an advantage, however temporary, by changing the rules slightly. For example, in the arcade game Assault, your highly- manueverable tank can enter "jump zones" that propel it above enemy vehicles on the ground, giving the player a unique advantage. Players want the biggest guns and the best armor. Give them a way of earning that advantage, and then give them a reason for really needing it. When placing constraints on the player's action, there must be a rationale. The premise may help establish why these constraints exist. If the player's magic hammer has been able to smash all walls, then it has to work all the time unless a "Special Wall" is encountered. The hammer must react with the wall in some way, perhaps signaled by a different noise or animation sequence. If something has worked in the past, it should work the same way in the future, unless some kind of new variable has entered into the picture. Make that variable clear, but you don't have to give away all its secrets. Don't forget to emphasize the heroic, epic quality of the player's struggle. Explosions must be large and gratifying. Climactic duels with the villian must satisfy! The player wants to look good, so provide those opportunities that reward dexterity, cleverness, and experience. Japanese arcade games often reward pattern memorization. Instead of providing a way out, many of the Japanese arcade games rely heavily on memorization to advance. The reward is for experience, not necessarily cleverness. By varying a set of patterns, you can make the game more dynamic and still reward memorization. For example, in Prince of Persia, fighting the first few swordsmen is fairly easy if you recognize a pattern in their fighting style. Later swordsmen have slightly different appearances, and have different patterns. I remember encountering the fat swordsman for the first time and getting slaughtered when I fell in my old patterns. The best patterns, in my opinion, are the ones that don't rely on a fixed sequence of actions or moves. The player instead recognizes of a particular tactic or set of circumstances that allows him/her to act prudently, while retaining flexibility in the goal-setting process. An excellent example is X-Wing. A particular Imperial tactic that is used over and over is the launching of TIE bombers after a wave of TIE fighters. The TIE fighters are a mere annoyance compared to the bombers, but the Fighters must be dispatched lest they attack lightly-protected Rebel vessels. Depending on distance and mission, the X-Wing pilot has to react based on the experience that has been drilled into him or her. Graphics and Sound The demand for high quality graphics and sound in today's oftware has advanced hundreds of times in capability since the early days of personal computing. We are no longer required to use our imagination to equate a blocky, low- resolution screen image with a rich fantasy world. Today, we fully expect to see recognizable animated images, and we increasingly demand music and sound. Games have become less abstract and more complex, made possible by faster computers and near-photorealistic graphics. The visual and audible aspects of a game should mesh smoothly with all previous aspects of the game. They should not be the primary focus of the game. Great graphics and sound should enhance an already great gaming experience, not usurp it. A mediocre game with great graphics and sound becomes a "technology showcase" with limited play value. A brilliantly-conceived game with poor audiovisual design limits its mass appeal. Having "good" graphics does not necessarily require millions of colors and high resolutions. The graphics must reflect the premise and setting of the game. They must be clear, well-rendered, and stylistically consistent. Great graphics will transcend the limitations of resolution and color. The games from LucasArts are among my favorites. Although they are seen on a 320x200, 256 color IBM-PC display, the characterization and visual design stands on its own. The chunky pixels and blocky graphics fade from consideration because the game successfully pulls you into its world. Engagement of the Senses To engage the senses is to invite the player into the game world. The vicarious experience of the player must be consistent in presentation and context. This is a balance between all the elements discussed above: Player and Environment, Story/Setting and Player Expectation, Goal- Setting and Gameplay, Graphics and Sound. The game designer can also exploit second- and third-order experience. These are the subtler details that are not immediately obvious, but nevertheless contribute to the depth of the gaming experience (the term "second-order" is a mathematically expression. In engineering, it distinguises between a simple model and a more accurate but complex one.) An excellent example of this is Street Fighter II. On the surface, this game is just another chop-sockey kung-fu fighting game. This is a simple categorization. When it was first introduced, it distinguished itself from other games by offering silky-smooth, state-of-the-art animation. This naturally attracted players. What distinguished SF2 from other "hit-the-button punch-punch-punch" games was its outstanding second-order design. It wasn't enough to just