Public Domains: Gacha Game is a mobile RPG that uses public domain art assets. It is an April Fool's Joke.
All art is in the public domain. The only original artwork created for this game is the logo, which I guess is also in the public domain because sure. All code is licensed under the GNU Affero General Public License v3.0, with the exception of a chunk at the bottom of rendering.js, which is licensed under the MIT License. The Press Start 2P font font is licensed under the SIL Open Font License 1.1.
There is no building. Just open index.html in a browser. No nodes, no package managers, just eight JavaScript files. If you're on a desktop browser, you're probably gonna want to use the developer tools to emulate a mobile device.
Just create a new Cordova project, copy the index, js, and img folders into the project's www folder, uncomment the cordova.js include line in index.html and then build for whatever platform you want. It definitely works on Android, but has not been tested on iOS.