Mattel163: Phase 10 Mobile

How to build a mobile game from zero to ONE and grow its loyal fanbase

Project
Phase 10 Mobile Game

Role
Team Management, Art Direction, Interaction Design, and UX Research

Team
Senior UI Designers (2), 2D Animator and Concept Artist

Date
October 2018-March 2020

problem

Phase 10, a rummy-style card game with a dedicated but niche fanbase, faced the challenge of expanding its appeal without alienating its core players—primarily women aged 20 to 40 who enjoy casual strategy games. To win in the physical card game, players played through all ten phases which could last hours and days. Our challenge was to create a mobile version that stayed authentic to the game’s roots while attracting new players.

Additionally, to coincide our launch with the newly designed Phase 10 cards, the game had to be finished within seven months.

Goals

Player Retention & New Player Appeal

  • Maintain loyalty among existing Phase 10 players.

  • Create an intuitive onboarding experience to attract and retain new players

Play Anytime, Anywhere

  • Design for short, flexible play sessions (3–5 minutes)

  • Implement offline play with an arcade mode

  • Optimize for portrait orientation to support one-handed gameplay

Continuous Usability Testing:

  • Conduct regular player tests at critical development milestones

  • Use player insights to inform design iterations and improve gameplay experiences

PROCESS

Team Growth
At Mattel163, I had the opportunity to build a team, overseeing art direction, hiring, and UX. With an aggressive timeline, I recruited a lean design team comprising of an animator, UI designer, and concept artist with skills to integrate art directly into Unity for seamless collaboration with engineers.

Design & Development
At the Mattel HQ, I partnered with the Mattel brand team to finalize a style guide that ensured visual consistency between the mobile game and the physical card game. The Mattel product team became user testers and stakeholders in making sure the product was a great fit for mobile.

The design team achieved this by creating wireframes to validate key features, including portrait orientation for mobile playability. We prioritized social features so that physical card players can easily start private games with family and friends.

Iterative Usability Testing
With each development milestone, the UX Researcher and I ran usability tests (RITE) with real players to identify pain points and track improvements across sprints. We then delivered weekly UX research insights to the Production Team in Hangzhou.

DESIGN

Onboarding Experience

For the uninitiated Phase 10 player, the experience needed to teach them the unique rules of gameplay within the first game of 2-3 minutes to get their attention. We created a comprehensive tutorial explaining game objectives, rules, and terminology. We also created a progressive map to help teach new players what they can expect in the next game as the rules become more complicated.

Art Direction

Led the creation of a clean, simple, and relaxing art style, aligned with the expectations of casual game players

The final design was visually soothing, making long play sessions easy on the eyes

Metagame Features and Live Operations
Led the creation of a clean, simple, and relaxing art style, aligned with the expectations of casual game players

The final design was visually soothing, making long play sessions easy on the eyes

Gameboard UI Space

A huge challenge with a mobile card game is the legibility of the cards, especially when you can have up to ten cards and four players at one time. We designed three layout options to test.

UI Art Style Guide

While the gameboard was being designed, the Senior UX Designer began to specify fonts, colors, buttons, icons, and key modals into a comprehensive style guide for the team. Because we had a small team and an aggressive timeline, a style guide allowed cross-functional teams to scale the game rapidly.

Social Interactions

Focused on fostering familiar, comfortable multiplayer experiences by enabling private games with friends and family. Integrated leaderboards to add a light competitive edge without overwhelming casual players.

Players can start a game with their friends by inviting them to a game room

Players can start a game with their friends by inviting them to a game room

The host player can do three actions: 1) Select number of phases 2) Invite Friends 3) Emote with quick phrases and emojis

The host player can do three actions:
1) Select number of phases
2) Invite Friends
3) Emote with quick phrases and emojis

Tapping the ‘Edit’ pencil icon allows players to change the number of phases. We wanted to limit the number of phases allowed since the full ten phrases between three players would be difficult to complete.

Tapping the ‘Edit’ pencil icon allows players to change the number of phases. We wanted to limit the number of phases allowed since the full ten phrases between three players would be difficult to complete.

Tapping on the ‘Add Friend’ icon at the top will prompt ‘Invite Friends’ popup. Inviting online friends would appear first in the list. Offline friends will receive a server-side push notification asking them to join the game.

Tapping on the ‘Add Friend’ icon at the top will prompt ‘Invite Friends’ popup. Inviting online friends would appear first in the list.
Offline friends will receive a server-side push notification asking them to join the game.

Invited friends would receive a drop down notification to ask them to join. If they miss it, the message will be in their inbox.

Invited friends would receive a drop down notification to ask them to join. If they miss it, the message will be in their inbox.

Once the invited friend joins, they will need to wait for the host to start the game. Meanwhile they can chat with other players.

Once the invited friend joins, they will need to wait for the host to start the game. Meanwhile they can chat with other players.

Outcomes

Retention
8 out of 10 players in post-launch tests played at least 1–2 hours per day, despite challenging levels. Players leveled up quickly, indicating strong engagement, overall comprehension of game rules and finding the fun in the game.

Production Output
With a clean, simple art style based on a 2D pipeline, the team was able to stay small while content output was high with new skins, worlds, and avatars. The "World Tour" feature introduced new events, challenges, and rewards, keeping gameplay fresh. The game launched in June 2019 after six months in development.

Successful Product Impact
The mobile app attracted a substantial global audience, enabling active online multiplayer experiences. In 2022, the "World Tour" highlighted Phase 10’s history, appealing to both new and veteran players. From 2018-2022, the game remained one of the Top 10 card games in the Apple’s App store.