Go 3D Game Engine
2D Platform Game developed in Unity for Android, Windows, and Linux
DOOM / Heretic / Hexen source port with enhanced graphics and UI
3D C++ Game Engine - yet another open source game engine
Teach retro game development with streamlined workflows
Rewrites the light engine to fix lighting performance
Commander Keen Interpreter
Amazon Lumberyard is a free AAA game engine
ZED OS the clone of Windows XP
mGSTEP port of the Cube game engine
FreeCS is a free-software reimplementation of Counter-Strike 1.5.
A fast-paced free software rally racing game
Open RealStrategyGameLibrary (Engine)
Improved version of the X-Ray Engine, the game engine
Simple Minecraft-inspired program using Python and Pyglet
Modern 3D engine and IDE written using C# and C++.
An open source re-implementation of Diablo 2
Data-oriented and data-driven game engine written in Rust
2D Game Engine with Lua Scripting made on top of SFML
A cross platform Lua based game engine
3D playground built on three.js and cannon.js