The main branch uses Processing in Java to demonstrate a rudimentary platformer. The "Godot" branch does the same with the lightweight game engine Godot.
If you're interested, clone this repo and have fun with it. I've used this repo as a teaching example for OOP and core game design.
UPDATE 11/4/24: When I have time, I'll make a fully playable game with storytelling. After completing the Godot branch, this will be transitioned to a 3D platformer with Unreal (that won't be open source 'cause it's Unreal). My goal is to make it playable on my website, but I have uni + work + startup stuff in the way.