Godot is a powerful cross-platform game engine
A cross-platform PSP emulator
Stream switch games to your PC via USB or network
An open-source sandbox tower defense game
UCI chess engine
Open source voxel game engine with support for survival and crafting
A simple and easy-to-use library to enjoy videogames programming
A certain block game
Xash3D FWGS engine
Portable UCI- and XBoard-compatible chess engines.
Open source cross-platform multi-purpose game toolkit
Desktop/Android/HTML5/iOS Java game development framework
RetroArch is a frontend for emulators, game engines and media players.
Sandbox video game with a powerful physics engine
Voxel game-creation platform with easy modding and game creation
Multi-platform 2D and 3D game engine
The game engine for everyone
Do virtual gear shifting (and more) in any rider app
An open source reimplementation of the Among Us Server
Open-source Android/Desktop remake of Civ V
One framework for creating powerful cross-platform games
Open source HTML5 game framework that offers WebGL and Canvas
Home theater software and entertainment hub for digital media
The source code to VVVVVV
An iOS & tvOS Frontend for Multiple Emulators