lilypond

lilypond is a free and open source (GNU GPL v3 licensed) game created that everyone can play, modify, and make their own games from. It comes with its own platform-independent game engine written in C using SDL 2. It also has a platform-independent level editor written in Rust.

You can also play it directly on the web here: https://lilyfarm.org/static/lily.html and get the source code here: https://github.com/jadidbourbaki/lilypond-public

lilyfarm is an organization dedicated to creating Free and Open-Source Software (FOSS) that helps make the lives of working class people better.