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Games for All

An exploration of accessible game design patterns to create more challenging and intuitive game experiences. Our goal is to promote inclusivity in the gaming community and provide more equitable and enjoyable experiences for all, especially people with upper-body motor mobility disabilities.
I am responsible for conducting playtests and interviews, writing documents, and UI programming in Unity. 


User Researcher & UI Programmer






Aug 2022 - Dec 2022

Team Size




For people with upper body motor mobility disabilities, enjoying video games can be challenging. Due to the complexity and diversity of their individual situations, customized game controls and play are often necessary to ensure an accessible and enjoyable gaming experience. How might we design a game that they can easily enjoy?


We came up with 2 tested design patterns that can aid people with upper body mobility disabilities, which are adaptive accessibility settings and automatic button mapping. 

End Result
Uncovering Issues

01 Background Research

we visited Intermediate Unit One (IU1), a local public school that has multiple disability support classrooms, to conduct our primary research. During the visit, we discovered that while many of the children in the classroom faced motor mobility challenges, most of them also had neurological disorders, which made it difficult for us to interview or playtest. Luckily, we were able to observe their interaction with the assistive technology and interview their teachers

We found that they all have highly diversified disability situations and we were unable to categorize their ability.

Tablet apps to promote concentration

Eye-tracking Device


Big buttons for simple reactions

We then seek help from subject-matter experts Dr. Patrick Carrington and Ph.D Franklin Li from CMU Human-Computer Interaction Institute (HCII) on this matter. However, they informed us that due to the complexity of hand function, it is difficult to properly categorize upper-body motor mobility disabilities. This insight is important as it highlights the complexity and diversity of needs among users with upper-body motor mobility disabilities.

As designers, we need to take a flexible and adaptable approach in addressing the needs of these users, recognizing that their individual abilities and preferences may vary widely and there is no way for us to design solutions based on each of their abilities.

Interview with Dr. Patrick Carrington

Interview with Ph.D Franklin Li

Then we dive into the established guidelines for accessibility in gaming industry. We followed APX model by Ablegamers. It is a set of 12 design patterns that help developers create accessible games for players with disabilities. The design patterns cover aspects such as input options, control options, feedback, and difficulty. The APX model is based on research and user testing by Ablegamers, a charity that aims to combat social isolation by empowering people with disabilities to enjoy video games. 

Source: APX Model by AbleGamers

02 User Research

Through the connection to a previous project that aimed to develop a wheelchair activity, we got into contact with Jen, who is a wheelchair user with an upper-body motor mobility disability and plays games weekly. We conducted an interview about the way she plays games and some of the issues she ran into in the past.

Conducting User Interview

We found that she usually plays relatively slow-paced games that don’t require 2 hands to maneuver at the same time, such as Civilization 5, and city builder games. She also enjoys playing World of Warcraft, although she has to seek some additional help from her husband while playing WOW. She doesn’t play FPS games because they are simply too hard for her to maneuver.

As we observed her playing games and had conversations with her, we noticed some difficulties she had when playing games.

  • Strength: Jen doesn't have enough strength to press certain buttons, and holding a bigger controller for a long time is challenging.

  • Complexity: The game gradually becomes too complex for Jen to control. For example, Final Fantasy 14 starts off well, but then becomes too complicated. She can't play anymore because it requires too much maneuvering.

  • Accidentally hitting buttons: This is especially true with the Xbox controller. The shape of certain buttons is hard to hold, and Jen ends up pressing the wrong button accidentally.

Observe User Behaviors

  • Control mapping & remapping: The process is tedious for Jen and is one of her pain points, which prevents her from playing certain games. If a game's controls cannot be easily remapped to suit her needs, then she has to give up the game.

Exploring Process #1 - Adaptive Accessibility Settings

How might we create a game that caters to diverse players and provides an ideal gaming experience for all?

01 Ideatioin

Since our team was small and only had 14 weeks, we recognized that designing a complex accessibility feature system like those found in The Last of Us Part 2 or Far Cry 6 may not be feasible. As a result, we decided to take a different approach and focus on smaller, but still impactful, design elements.

After a timed brainstorming session, we decided to focus on creating an FPS mini-game, as this genre is currently one of the least accessible to people with upper-body motor disabilities. We also recognized that the "Git Gud" culture and high level of hand-eye coordination required in this genre are highly exclusive. However, the action of shooting is highly interactive and fun in its nature. So we don’t want our disabled players to miss out on that fun.

Brainstorming Game Ideas

With this in mind, we set out to create a game system that could automatically adjust difficulty levels to match different players' skill levels, without them noticing at first glance. Our goal is to make the game more inclusive and accessible for a wider range of players, and to challenge ourselves to design a more innovative and adaptable game system.

We added a "calibration" level to the game as a foundation for the entire system. By completing this level, players provide the system with data that can be used to automatically adjust the accessibility settings in the main game levels. This allows for a more personalized and inclusive gaming experience for players of all skill levels.


Personalized Profile



02 Prototyping

We then built prototypes to test out our hypothesis for solving the problem. We built a simple calibration level and then collected data from players at the backend. We did some research on the current FPS skill evaluation system, such as Aim Lab and 3D Aim Trainer, and chose the following parameter in our model: Max Hit Interval, Hit Target, Target Average Lifetime and Accuracy. Using these data, we developed a mathematical model that could predict a player’s performance.

Calibration: Collecting Data

We collected data from 30 participants to linear fit the mathematical model and then obtained another 10 sets of data from 10 participants to validate the mathematical model.

Estimated Score VS Actual Score

We measured the standard error of our model, which is a statistical measure of how far off our predictions may be from the actual results. The result was 1.25, and we felt confident in its ability to make a rather accurate prediction.

So we went on to develop an actual mini-game. In the game, after the player completes the calibration level and each level in the minigame, the system uses the data to make adjustments to the target size, moving speed, lifetime, and aim assist. This way, the mini-game can adapt to each player's skill level and preferences, creating a more personalized and enjoyable experience.

Calibration: Collecting Data, High-Fi

Aim Assist

Moving Speed



03 Testing & Iteration

We conducted playtest sessions with Jen, some college students, and nearby community members who don’t play FPS games often. Before the playtest, we didn’t tell them that the game would dynamically change difficulty according to their performance on the calibration level and each level. The total number of playtesters was 11.

None of the playtesters noticed the target size, moving speed and lifetime were changing when they were playing. However, the aim assist system became too obvious as they played. In the last part of the mini-game, 6 out of 11 playtesters talked about feeling out of control

We used the NASA TLX (Task Load Index), a well-known assessment tool, to measure the subjective difficulty of the game. By using this tool, we were able to get feedback directly from players about their perceived difficulty level. All of the playtesters felt comfortable about the game difficulty, feeling challenging but manageable at the same time. The results of their TLX fell in the range of 4-6 out of 7. In particular, one of the playtesters, who was hesitant to try the prototype because they felt they were bad at shooting games, felt more comfortable and confident after playing our demo. 

Based on the testing results, we decided to make some adjustments to the aim assist system by adding an option menu that allows players to toggle on and off the aim assist. Also, to be more transparent with the players, we added the dynamic difficulty option in the menu too. 

I programmed the functional option menu system in Unity.

​Exploring Process #2 - Automatic Button Mapping

Another difficulty Jen mentioned that we think we can address is control mapping & remapping. The process is tedious for Jen and is one of her pain points, which prevents her from playing certain games. If a game's controls cannot be easily remapped to suit her needs, then she has to give up the game.

How might we create a game that streamlines the tedious process of mapping and remapping controls?

01 Ideation

Building on what we learned about accessibility from our previous prototype, we incorporated a tutorial-like automatic button mapping system into the second exploring prototype. Our team recognized the need to improve the button re-mapping process, especially in genres such as third-person isometric platformers, where complex controls can be a challenge for disabled players. With this new system in place, we aim to reduce barriers to remap and create a more accessible and enjoyable experience for all players.

Current player flow

Target streamlined player flow

The composition box of our target experience, with peer feedback

02 Prototyping

The button mapping process in the tutorial of our platformer consists of 2 parts, which are automatic button mapping and confirmation

When first introduced to a new action, the player can press any unmapped button and try. The UI will update according to the button the player just pressed.

The mission HUD will keep track on the confirmation process. If the player press the same button 3 times in a row, then the mapping is confirmed.

Due to a temporary lack of available playtesters with upper-body motor mobility disabilities, we conducted a paper prototype testing of remapping during game with non-disabled testers with specific constraints. We limited participants to using only two different buttons and a joystick to complete the given task, which is to remap a certain action to another button. We tested 3 players and asked them several brief questions about the process. 

All users were able to complete the task, resulting in a 100% task completion rate. However, one user took longer to complete the task and had a higher error rate compared to the others. Overall, users expressed satisfaction with the prototype and believed that it was quicker than the traditional method of remapping buttons and trying out new settings.

Paper prototyping and testing

03 Testing & Iteration

We tested the prototype with Jen, college students and nearby community members who don’t have much experience playing platformers. We asked the non-disabled playtesters to play with the Xbox adaptive controller and Logitech adaptive gaming kit, they could choose whether to play with only one hand or not. In this way, we can gain some insights on the subject we wanted to test. After the playtest, we conducted a System Usability Scale (SUS) survey and a brief 15-minute interview session. The total number of playtesters was 15. 

Xbox adaptive controller and logitech adaptive gaming kit

Our prototype received positive feedback regarding usability, except for one area - complexity. Playtesters reported that the system was unnecessarily complex, which was understandable. This was because, for non-disabled individuals, most of them don’t need to remap any keys when playing games. Therefore, the added complexity of the system was not seen as beneficial by these users. Though the average score of complexity is not high, 65% of the playtesters didn’t think it was overly complex.

We also made two changes to the onboarding process based on our observations and interviews.

Change 1:

Replaced in-game action with the actual buttons to press so there is less translating in the brain.

Change 2:

Provide players ‘expectations’ for the mapping actions.

In the interview after playtesting, Jen said, "I really like the additional program for easily setting up custom buttons for control. That is something that is often forgotten or poorly implemented. In this case, it was very easy to set up, very quick. It really worked well."

Lessons Learned

Designing, implementing, and testing accessible features can be a time-consuming and resource-intensive process, but it's a crucial investment in creating a more inclusive gaming experience. 

As we worked on our project, we quickly learned that even small accessibility features can have a big impact on players and their ability to enjoy the game. It's important to approach accessibility with an open mind and recognize that it may uncover related issues that need to be addressed.

Knowing when to persevere and when to pivot is also key in managing the project's scope and resources effectively. 

In the end, the demand for accessible gaming experiences is growing, and we believe that our efforts will benefit not only our players but also the gaming community as a whole

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