Godot is a powerful cross-platform game engine
Stream switch games to your PC via USB or network
A cross-platform PSP emulator
Xash3D FWGS engine
A simple and easy-to-use library to enjoy videogames programming
Desktop/Android/HTML5/iOS Java game development framework
UCI chess engine
Open source voxel game engine with support for survival and crafting
Do virtual gear shifting (and more) in any rider app
One framework for creating powerful cross-platform games
RetroArch is a frontend for emulators, game engines and media players.
Open-source Android/Desktop remake of Civ V
Home theater software and entertainment hub for digital media
The game engine for everyone
Sandbox video game with a powerful physics engine
Voxel game-creation platform with easy modding and game creation
Open source HTML5 game framework that offers WebGL and Canvas
The source code to VVVVVV
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Multi-platform 2D and 3D game engine
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
Netcode that provides networking capabilities to GameObject workflows
A dead simple 2D game engine for Go
Cocos simplifies game creation and distribution with Cocos Creator
Free, cross-platform 2D game engine powered by Haxe and OpenFL