A certain block game
RetroArch is a frontend for emulators, game engines and media players.
Open-source Android/Desktop remake of Civ V
Xash3D FWGS engine
One framework for creating powerful cross-platform games
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Do virtual gear shifting (and more) in any rider app
Open source HTML5 game framework that offers WebGL and Canvas
Desktop/Android/HTML5/iOS Java game development framework
Free, cross-platform 2D game engine powered by Haxe and OpenFL
The source code to VVVVVV
A dead simple 2D game engine for Go
Cocos simplifies game creation and distribution with Cocos Creator
Open source library for creative expression on the web, desktop, etc.
Cross-platform game engine in Rust
Domination is a game that is a bit like the board game Risk
Your collection, your way
3D Engine c++
GemRB is a portable open-source implementation of the Infinity Engine
Android, UIQ 3.0, Series 60 Edition 5 open-source software
GEDKeeper - opensource and crossplatform genealogy management program
A MUD client for Android, iOS, Linux, Mac OS X and Windows
Orx: Data-Driven Game Engine
Old style soccer game with many exciting features