Though arcades don't maintain the same presence in the West as they once did, the key takeaways of coin-op design are as valuable today as ever. In this reprint from the October 1996 issue of Game Developer magazine, Jeff Brown and James Plamondon outline 'The Four Laws of Coin-Op' to be broken at the designer's peril. If you've ever played Star Castle, Defender, Mortal Kombat or Daytona USA, then you've experienced the pulse-pounding rush of great coin-op game design. As a PC game developer yourself, you know a good game when you see one. But knowing it's good and knowing why it's good are two very different things. Being able to design a coin-op game yourself is something else entirely. This article reveals the secrets of the coin-op masters. It is based on a series of interviews with some of the most successful coin-op game designers in the world. With high-end PCs emerging as the new standard platform for coin-op game design, your experience in PC game development and the experts' experience in coin-op game design should produce a new market for PC-based coin-op games that can be very profitable to both—and a heck of a lot of fun.

It's the Law

We interviewed many stars, such as Ed Logg, designer of Centipede, Gauntlet, and Steel Talons, Richard Ditton, founder of Incredible Technologies whose credits include Capcom Bowling and Time Killers, as well as designers at Williams and Rare (makers of Killer Instinct). We asked specific and open-ended questions about what coin-op games were the best and why -- and what general rules they used when designing coin-op games. The answers, while varying widely, uniformly agreed on the key concepts described below. These, then, are the core design principles -- the laws, if you will -- of coin-op game design. As with all laws, you can break them if you wish, and you may even get away with it -- but you're running a nearly 100% risk of failure if you violate these laws without first internalizing them completely.

Brown's First Law: Be Simple and Intuitive

A coin-op game's controls, objectives, choices, and reasons for loss must be simple and intuitive on the first play. Nobody reads the instructions in a coin-op game, at least not until they've played the game and realized that the controls have greater depth than they first imagined (see Law #4, Depth, below). Players have to be able to walk up to the machine, drop in a coin, start playing, and do well enough on the very first play to feel good enough about their performance to think that they (and therefore the game) are pretty darn good. If a game fails to obey this law, the players will walk away after their first coin -- a recipe for financial disaster. Capcom's phenomenally successful Street Fighter II provides an excellent example of this law in action. Its controls consist of a joystick and six buttons. The joystick moves your fighter's body, and the buttons activate kicks and punches. The six buttons are arranged in two rows. The three upper buttons control punches, while the three lower buttons control kicks -- so there's a natural mapping between upper body (which correlates to the upper buttons) and lower body (which correlates to the lower buttons). From left to right, the buttons progress from faster, lighter blows to slower, heavier blows. Anyone can just walk up to Street Fighter II and do pretty well in the first couple of rounds against the computer just by pounding quickly and randomly on the buttons. Once they've played a few times and have built a desire to improve, players might read the few simple instructions (or simply explore the controls' behavior) and realize that the controls have greater depth. The objective of the game is obvious to even the most casual passers-by. Two large, tough-looking characters start each game facing each other in stances that suggest impending confrontation. Even from the early days of the fighter genre, this was more than enough to teach a player what he was supposed to do: use his character to beat the crud out of the other character. Distinct life energy bars on each player's side of the screen and a large centralized timer communicate the specific objectives—namely, pound your opponent until his life energy is gone, or at least drive it lower than your own bar before time runs out. The primary choice in Street Fighter II is which character to use, and this choice is presented in a simple, obvious manner. Afterwards, the player chooses which attack to use at which time -- the basic attacks, character-specific attacks, and combo attacks. These decisions can be the result of randomly pounding the controls or of extremely deep (but fast) tactical planning, depending on the skill level of the player. Each individual attack is easy to learn, and the degree of improvement resulting from the player's learning just one move is significant, encouraging players to learn more. The learning curve is smooth, allowing the players to improve their understanding steadily, and at their own pace. A cardinal rule of coin-op -- almost worthy of its own law -- is that when a player loses the game, it must be obvious to that player why he or she lost, and it must appear to be a simple matter to correct the mistake and win next time. The player has to feel that he or she lost, not that the game won. The failing is with him or her, and the player should feel that with just a little more practice -- "just one more quarter" -- he or she can win the game (that is, overcome the specific challenge that defeated him or her last time).

Brown's Second Law: Deliver Strong Feedback

Strong feedback must be fast, accurate, detailed, and consistent—involving the player's senses as fully as possible. Of the five senses, three should be engaged in coin-op games: sight, hearing, and touch. (The frontiers of smell and taste are so far unexplored, which -- considering the content of fighting games -- is just fine with us.) Every player action must be reinforced by visible action -- an appropriate sound and, ideally, force-feedback. Force-feedback is best known from driving games, in which the steering wheel shakes from the "strain" of a tough turn, or jumps from bumping against other cars, and so on. This multi-sensory feedback links the player and avatar -- the vehicle, character, or icon. Through the avatar, the player is linked to the game environment. Only through fast and accurate feedback can the player get lost in the experience the game offers. Sega's Daytona, one of the most successful driving games ever, is a great example of this design law in action. It puts out a flicker-free 60 frames per second on a 50-inch, high-resolution monitor, giving the player very fast, accurate visual feedback. The high-quality audio system delivers important audio feedback, such like squealing sound when the player's car starts to slide. Force-feedback "pushes back" on the steering wheel, in response to the stresses affecting the car in the game -- from pulling Gs in tight turns to bumping against other cars. This multisensory feedback gives the player fast, accurate, detailed, consistent -- and therefore immersive -- information about his car and its interaction with other game elements. As a result, Daytona is widely regarded as one of the best coin-op games of all time -- and it's been making money steadily for two years.

Brown's Third Law: Deliver Pace and Rhythm

A coin-operated video game must deliver challenges to the player at a fast, steadily increasing pace, delivering rhythmic pulses of additional challenges. People play games to be challenged. These challenges can be mental, physical, or both. Mental challenges usually take time to work out. Myst is a great example of a mentally challenging game. It's also a great example of a game that would flop miserably in coin-op, which is why coin-op games invariably prefer physical challenges -- challenges of eye-hand coordination -- to mental challenges, as the core of game play. Since such a physical challenge can be presented and overcome in a fraction of a second, such challenges must be presented at a rapid pace. "Tuning" a coin-op game means sustaining the right balance between challenge and reward, at all points in the game, for the largest group of people who might play the game. Tuning has to make both the first-time player and the master player feel challenged and successful, while still defeating them in (generally) one-and-a-half to two-and-a-half minutes per credit. Atari's Area 51, a recent gun game, has succeeded in large measure to its excellent tuning of pace and rhythm. The pace of challenges is slow at first, and picks up gradually both in the short term (during the course of a single play) as well as in the long term (over multiple plays, as the player advances farther into the game). Both the rate at which enemies appear on screen and the speed with which they shoot at you after they appear are used to increase the pace. Threats come in distinct waves, ranging in intensity from light (enemies come more or less one at a time) to heavy (Yikes! They're all over the place!). Players do well enough during light and medium waves to feel good about their abilities and know that even a small improvement in skill ("just one more quarter...") will get them past the wave that they failed to shoot their way through last time.

Brown's Fourth Law: Offer Depth of Play

To continue to draw in coins, a coin-operated video game must engage a player's interest even after repeated play. "Depth" is that characteristic of a game that keeps it interesting and challenging. Depth can be provided through physical challenges or mental challenges. Mental challenges should offer a simple choice between obvious alternatives. The three kinds of mental challenges most effectively employed in coin-op game design are set-up options, mid-play options, and hidden elements. Set-up options include things like different teams, racetracks, or characters. In a racing game, a given car may do better on one track than another; having the player choose both the car (c) and the track (t) creates (c*t) combinations that the player can explore. Similarly, mid-play options give players simple choices during the course of a game. For example, in a racing game, the track may include a long easy stretch and a relatively difficult shortcut, tuned such that only the skilled player would be able to save time by taking the shortcut. Hidden elements are things like secret rooms, secret characters, and so on which generally require that the player know special information. These frequently are revealed only by extensive gameplay and word of mouth, creating an "inside group" of which many players will wish to be a part. Physical challenge not only forms the core of coin-op gameplay, but is usually the primary contributor to depth as well. Consider the simple and obvious controls of Capcom's Street Fighter II. Anyone can walk up, pound away at the buttons, and get at least a few good blows in, by luck alone. But to truly master the controls -- to be able to deliver a specific three-blow combination perfectly timed to maximize its effect on the opposing character -- takes a great deal of physical skill. This skill can be acquired only through extensive practice, which trains the player's muscles to perform the needed actions smoothly. But the separation of mental and physical challenges is not pure, quite the contrary. The pinnacle of mastery is achieved only when the mental challenge of selecting the ideal action, and the physical challenge of delivering it, merge into a mentally elevated state of being (not to get too Zen-like here), in which you simply are the character, and simply do the right thing. As Miyamoto Musashi, the legendary samurai duelist, wrote in his Book of Five Rings (1643):

The game designer's challenge is to create a game that is sufficiently compelling, that the player is stimulated to play again and again, in order to reach and enjoy this level of mastery.

Learning By Example

This brief overview of the Laws of Coin-Op is now complete. To understand these laws fully, however, it would be useful to discuss how the Laws would be applied to existing PC games in the main coin-op genres, to turn them into potentially successful coin-op games. Space does not allow such a discussion here, but you'll find exactly that discussion -- plus information on the great guys who contributed their wisdom and experience to the creation of this paper -- elsewhere online. You'll find these examples and a lot of other information on the emergence of the high-end PC as the new standard for coin-op video game deployment. If you're working on an arcade or action-style game, you should be thinking about coin-op -- and the information on our Web site will help you get started.