This project was born from an idea to make a WarioWare-style Gameboy homebrew title with microgames contributed from various developers. It started as a game jam and ended up as a finished game.
A secondary goal for the project was to serve as a learning resource for newer GBDK devs. Contained in this repository is code that covers multiple genres and multiple coding styles. There's probably something valuable in there for you, unless you're already a GBDK master. Though as a personal disclaimer: there's some jank in the engine code, but I tried to at least call it out with comments. Do as I say, not as I do. ;)