How to scale graphics
To be investigated
https://github.com/AlmasB/FXGL/issues/546
Midi support
https://github.com/mgsx-dev/gdx-pd
Graphics
https://github.com/leonbloy/pngj
https://www.nayuki.io/page/png-library
Sprite Tools
Generating sprite animations to gifs
https://genuinecoder.com/how-to-create-gif-from-multiple-images-in-java/
Detection of sprite positions.
Support for web and mobile platforms (Android, iPhone)
It is a good idea to ensure, that Open Eggbert is runnable on web and mobile platforms.
2D physics engines
https://github.com/erincatto/box2d-lite
How to create a Java Platformer game
https://longbaonguyen.github.io/courses/platformer/platformer.html