Universal design principles on game design —- take Candy Crush as an example


In July 2018, a research of a typical “match 3 game” Candy Crush revealed an estimated revenue of about $930 in the past 12 months, from both the purchasing action from its users and the commercial profit from its advertisers. There’s also a whopping 9.2 million users spend more than 3 hours daily on the game according to the developer of this game (Cheema, 2019). The prosperity of internet technology development gave birth to the development of both stand-alone games and online games. Tracing back to the possibility and playability of games, I can see the process of the prevalence and maturity of the game market as well as their design logic. Curious about mobile games and the game development thereof, I hope to illustrate how the universal design principles and the design of PC and smartphones are being applied in game designs in this paper.

In the following part of this paper, I’ll first explain the current market situation and consumer habit to summarize the premise and growing environment of the game market. Then, I’ll focus on the de-blackboxing of video games developed in the past 10 years, using Candy Crush as the main example and conducting comparison and contrast between different devices and some contemporary games. Eventually, I hope to illustrate the specific adoption of universal design principles.


Game market analysis

United States was the top country for mobile game development, which varied from browser games, PvP (Player versus player) to MOBA (Multiplayer online battle arena games). The history of online games started in the 1970s and went through a flourishing period in the early 20th century. The development of mobile games profits from the development of mobile phones, including a higher resolution, accurate screen response and high-speed networks.

Graph 1: Worldwide distribution of games market revenue from 2015 to 2019, data collected by Newzoo and graph created by WePC.com

During the recent 5 years, the market share of smartphone games and PC games has continuously occupied a large percentage of total game market. Also, according to the research by WePC.com, 53% of game developers were developing games for PC and Mac, followed by 38% of them for smartphones and tablets. PC and smartphones have always been the 2 most popular platforms for game developing, which also lead to a compatible requirement on multi-platforms investment. Moreover, 72.3% of mobile users in the U.S. are mobile phone gamers (IAB(Trends), 2016). Although there is not a huge overlap on mobile games and PC games, there is a tendency to expand games’ adaptability on multi-platforms both for promoting and technology developing.

Graph 2: iPhone’s top grossing mobile gaming apps in the U.S., data collected by Newzoo and graph created by WePC.com

For all mobile games released in the U.S. market, Candy Crush has occupied the second and the fourth highest daily revenue. It is interesting to find that Candy Crush adopts a much easier game logic, technical demands and producing cost than Fortnite, the champion, while still occupies a great market feedback. What makes a simple “match 3 game” go viral and become a national-wide popular mobile game? The rest of the paper will explicitly explain it by de-blackboxing the design principle and the compatibility of consumers’ psychology.

Consumer insight

Graph3: gamers demographic in the U.S. by 2017. Data collected by Pew Research Center and graph are created by WePC.com

According to the research, 64% of the general U.S. population are game players. Most of them are younger people (below 50) and don’t possess an extremely high education level. Also, women usually have a higher evaluation of games that are well-designed, fantasy and call for the participation of a community or with a storyline. While most men overweight the competitivity over those factors.

Therefore, for game designers, it is important to accurately target users by identifying their internet acceptance, learning ability, and plot preferences. Generation Z game players tend to be accustomed to computational learning and are relatively easier to accept new things and operation methods autonomously. Not to mention that there are a great bunch of game users who witness the whole creation and development of the internet and internet products. As a result, almost all current game players own a general perception of computational techniques and have a strong anatomy of self-learning skills.

Furthermore, some game players used to spend time viewing game videos of peer players on YouTube, including reviews, trailers, instructions, etc., most of whom aged between 16 to 34 years. In conclusion, the game designers should both guarantee the game effect and also make the players pick it up and figure it out quickly. The adoption of long-accumulated computer using habit should fit the demand of game players and designers, out of this standpoint, take on the universal design principles and apply them to the new game development.

Match 3 game developing analysis

Game developers are always finding ways to attract new users and keep them active. There is a previous research paper conducting comparisons over 7 different “match 3” games. First, social network sites enable people to share their profiles and daily lives within a limited community. Usually, SNS (like Facebook) accounts are external tools that can be displayed in a player’s game profile and thus establish the relationship with the player’s friends in real life. Only with a few clicks, the players can then reach an emotional connection as well as deliver a real attraction to their friends with the game (Omori & Felinto, 2012). Second, games with a flexible concentration requirement and lower entrance bar will easily attract more “un-hardcore” players. Allowing consumers to spend little time on it for several minutes anywhere at their convenient, it simply attracts them by the game’s entertaining quality and casualness. Then, by interaction between the game and the player and the bonus mechanism, the continuous gratification keeps the players with a longer connectivity. Other than those, privacy and security, marketing virality, etc. also affect user’s activeness and attractiveness. In conclusion, despite game interface, there are mechanics, gameplay and ideal stories that taken into account when evaluating a good game. In the rest of the paper, I’ll focus more on the design principles, like software and hardware dependence, modules interaction and network communication, etc. on analyzing the specific application on the game industry.


The term affordance was first introduced by Gibson in 1977 to interpret the interaction of the environment and the user from the ecological psychology view. The prevalence of smartphones has drawn huge attention over the affordance for exploring user’s perception and adoption for ICT (Information and Communication Technology) products (Leonardi,2011), which can actually affect the usability of the products. The graphic interface design and interface interaction of game design mostly benefit from the capacity of the smartphone screen.

Graphic User Interface

The icon of the game is made up of three basic items of the game: two normal candies and a special one (which owns some special function). Here are several more examples of the icon design in the game.

With the emerging smartphone screen development, the screen resolution has been experiencing a rapid improvement from 1136*640 of iPhone 5 to 2436*1125 of iPhone X. The Apple corporation nearly doubles its presenting quality to reach the lucidity of object presenting. And the newest MacBook Pro 13’ has a higher resolution of 2560*1600. Other than the displaying quality regarding screen resolution between the mobile device and PC, the screen arrangement is also sharing a different ratio. The following is a comparison of the same module (the first stage of the map) of the game entrance interface. The left one is what displayed on a webpage that is more like a square shape and is organized as a plane layout, while the right one is compatible with my iPhone 8 that not only adopts a rectangle shape but also demonstrates a deepened arrangement that simulates natural physics law of a foreshortening perspective. Moreover, when zooming in the two screenshots, I can see there is a worse fringe color on the PC website since this display area has fewer pixels to hold different color dots to achieve a smooth transition. However, one thing that the PC webpage one overweighs the mobile one is that it reacts to the cursor and the click while the mobile one can only sense the touch/press. Both cursor and touch ask for the detection within a specific area that I’ll illustrate more thoroughly in the following parts.


The vibration of a smartphone is connected to the haptics. Inside a phone, there is usually a vibration motor inside the smartphone that controls the thousands of vibrations of our phone each day. The vibration in Candy Crush can notify an effective swiping together with the elimination of an array of candies. After the swiping triggers the backstage program, it analyzes whether a player’s action is effective or not together by delivering signals to the vibration program. If it is classified to be an effective swipe, it will both complete the exchanging action and the vibration, along with a slight sound effect generated by the speaker of the smartphone. If it is classified to be a noneffective swipe, it will neither complete the exchanging action nor make the sound effect, but will still activate the vibration motor that indicates the swiping action.

Other than that, the design of the smartphone inserts the functional module of the vibration motor, which not only helps with the convenience of smartphone users but also creates more possibilities for the application designers. I still remember when I first set up my iPhone, it asked me to customize some functions that are related to my personal habits. The vibration feedback is one of such examples. iPhone actually provides several vibration patterns for its users to choose from and apply to different occasions. It is not only a feedback or a reminder from the phone, but also an interaction between the user and the device which lets users know that they are participating in the design process of their devices and also improving the user experience.


For a long time, designers of physical products and internet applications have formed a common knowledge to adopt a strong consistency both from other pre-existing works and other parts of this system. Replicating and transferring the older services into a new context greatly increase the usability and learnability of a new application or product. Lidwell, Holden, and Butler classified the system consistency of design principles into 4 types: the aesthetic consistency, the functional consistency, the internal consistency, and the external consistency.

Aesthetic consistency

The aesthetic design on the interface of one application leaves the users a strong visual impression for the basic characteristics and functions. Previous researchers have concluded that visual aesthetics plays an important role in the evaluation process of users when they encounter an interaction system (Tractinsky, Cokhavi, Kirschenbaum & Sharfi, 2006). The consistency in Candy Crush reflects both in its icon design and its uniform style throughout the game.

For the simplest element—a candy, the designers rebuild a candy world by animating geometric figures with designed lightening effect to mimic the true candy shape. By means of the pixels and their capacity on the screen, one pixel can display 16777216 colors by changing the proportion of the primary colors (Red, Green and Blue) and their luminance by 256 extents. As human eyes are most sensitive to those colors, the huge variety of colors is enough for human eyes to recognize. Also, plus the high resolution of current electrical devices, the icons can present a 3D effect. By arranging the colors on different pixels, the designers create a vivid color effect including highlight and shadow of an object, thus can simulate what we see every day in our life.  Nowadays, designers are always trying to simulate human eyes effect to focus on the “human-centered” interaction and promote the communication between users and the machine. Creating an interface from the users’ point of view helps the users to understand the system without having a knowledge of the algorithm behind the interface or any complicated learning instructions. It helps the users figure out what something does, how it works and what operations and interactions are possible in this system (Norman, 2013). Not only the candies displayed on the game icon or the level composition, the obstacles and boosters also show a vivid simulation of real-world objects for user’s recognition.

Functional consistency

In an interaction system, there are always some signifiers that can be easily precepted by the users and explicitly illustrate their functions in the right place. The functional consistency uses symbols from previous social experience and asks the users to leverage them those previous knowledge in dealing with a new application. Common signifiers to some extent teach people how to control those functions in the new environment.

There are several main special candies in the game Candy Crush. Based on fundamental candy forms, there are advanced types of candies, such as striped candies (those with horizontal strips and those with vertical stripes), wrapped candies (those look like a bag of candies) and color bombs (the black chocolate ball covered with colorful sprinkles). Stripes candies allow users to eliminate an entire row or columns candies. We get to know the direction by observing the direction of the stripes: those with horizontal stripes can clear all candies of their rows and those with vertical stripes can clear all candies of their columns. Wrapped candies can explode and eliminate the 8 candies around it in a 3*3 rectangle range, it is designed like a shopping bag that can explode anytime and create a strong damage around it. The color bombs can clear all the candies with the same color after being swiped with a color candy near it. The large amount of colorful candies attached to the chocolate ball shows its capability to absorb a large amount of candies at one time. Beyond those, there are also various kinds of boosters, blockers and obstacles with different designs and t functions. Candy Crush hardly has any instructions for users to learn how to create or use specific items or boosters. A good functional consistency also focuses on creating an appropriate affordance to make the users’ desire doable with the technology used.

Internal consistency

We can see the internal consistency everywhere in a design: The icon of the game shares the same elements with the compositions, the character design and environment design both achieve a playful and colorful theme, not to mention the sound effects. All those elements are combined together and provide the users with a joyful consistency that also cultivates trust with the users.

External consistency

It is not an easy thing for various internet products are observed having similar design standards, but it is essential for users to have a continuous perception of using habits to let game designers apply those intelligence into new game creations. In the early 2000s, when emerging mobile games were carried by the improvement of smartphone techniques, they were also exploring the best-fitting way to help with the effective communication between users and machines, as well as encourage the appropriate feedback from the system. Before Candy Crush, Fruit Ninja and Angry Birds promoted the interaction between users and the game in virtue of screen-touching control technique. The development of touchscreen enables the installation of mass interaction application and better exploits the affordance and possibility of smartphone.

There are many substrates on a smartphone screen or other devices that support touchscreen function, in which the top several layers are transparent that catch electrically movement. When our fingers touch on the screen, there is a touch sensor that detects the presence or movement of one object within a touch-sensitive area. Therefore, it can catch the location, proximity, pressure magnitude, etc. of the object movement. In this way, our bodies get to connect with the computing system and become part of the design.

In Candy Crush, after the players making an “swiping gesture”, the screen then provides the feedback as the result of exchanging the position of two candies. However, the rules of the game restrain the effectiveness of the exchange. If the exchange action makes a three same matching in the same row or column, or combine two special candy to promote a stronger effect, the exchange is considered effective, vice versa and the two candy jellies return to their original position, and this noneffective swiping won’t be concluded in the movement limitation.

Some touch sensors include several electrodes on different substrates. By approaching the screen with our finger, there exist several electronic changes on different layers of the touch-sensitive areas and thus enables the screen to recognize our gestures and moving tendency. Fruit Ninja, similarly, uses a screen swipe to simulate the chopping action when a fruit is “killed”. The users first create a moving path on the screen, after the sensor detects and decodes it as a continuous action, the feedback would be a cut-up effect follows the line on the screen. So is Angry Birds. The successful action in Angry Birds requires the detection of both moving path and the intensity and touching time. No matter what, by copying some properties of familiar objects or operations, they mimic the users’ daily using habit and maintain a good user experience.

People are better at recognizing things they have previously experienced than recalling them from memory (Lidwell, Holden & Butler, 2010). In a complex system, it is important to make unfamiliar things recognizable. Often, encountering familiar options stimulates users’ acceptance and the decision-making process of a new product. Maintaining the consistency of application is thus important for designers to adopt previous game design construction and apply those experiences into new product creation.

Feedback Loop

Candy Crush is a game of luck, as the success of the level depends on the random candy pattern you are given. Actually, not completely random. The game researchers classified it as a behaviorist psychology strategy. It stimulates a positive feedback loop that encourages a repetitive behavior. The level is divided into several difficulties, at the beginning of the introduction of a new element, the game is at the entry-level to help the players develop substantial skills in recognizing and applying those elements. Then, it suffers a relatively higher difficulty to reduce the satisfactory and intrigue their competitivity. And at one time, an easier level will be needed again to maintain the player’s activeness and confidence.

When it comes to how to control the level difficulty, there are many patterns of the algorithm design that decide the overall difficulty of one level. For example, the players cannot predict the falling pattern of the candies. Every time a bunch of candies are cleared, there will be candies dropping from the very top and become part of the new candy pattern. Therefore, the game will be planning the dropping candies that decide whether the possibility of a user to complete the current level. For the users, they can either choose a riskier way without predicting possible falling patterns or resisting change and maintaining an equilibrium strategy in game playing. This is a mutual feedback that also requires a long-term memory and analysis of the player’s operating habits. It keeps the player assessing their plans and choices of the game strategy. It has long enticed the players to stick to this uncertainty.


Video games have been developing since the existence of internet and computational technologies. The construction of game design is built on the affordance and capability of current technology and decides the degree and development phase that a game can be supported. Learning from the previous experience, game designers pass the intelligence to new game creation and innovative application. Although it seems that Candy Crush has adopted a simple customer logic design, the development background is actually deeply rooted in the human primitive behavior pattern for a long time. Game company thus manages to demonstrate a lower development cost and let it become popular all in a sudden.

Those universal design principles and the examples provided above indicate the adaptability and continuity of some basic design rules: affordance to best apply the hardware capacity and software capacity into user interactive process, consistency to stimulate recognition and build trust with users and make the game more controllable and learnable, also, an appropriate feedback that keeps the stickiness and activeness of users by memorizing and analyzing their previous behavior patterns. This article decomposes the daily game habit into calculable and controllable rules and techniques that make what used to be obscure and hidden design logic more transparent. Therefore, it concludes several wide-applied design principles in the game design industry and retains the possibility to further optimize PC and mobile video games, but also helps with the forecast and evaluation of the consumer’s future performances and behaviors.



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