Jo Engine is an open source 2D and 3D game engine for the Sega Saturn written in C under MIT license. It allows to develop game easily without extensive knowledge in embedded development. And... games run on emulator and also on the original system !
Website: https://jo-engine.org/
Official Forum : https://forum.jo-engine.org/
Wikipedia: https://en.wikipedia.org/wiki/Homebrew_(video_games)#Sega_Saturn
