osu!, a rhythm game about clicking circles, has had a new client in development since 2014, aiming to fix some of the issues and “spaghetti code” the previous stable version had. The new client, Lazer, is open-source and works on Windows, MacOS, Linux, iOS, and Android. Lazer has finally been made the default download option for new players just starting the game.
I actually played the western release that came after that. Might get into the action of translating it: https://gbatemp.net/threads/recruiting-english-translations-for-osu-tatakae-ouendan-2.620347