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
A homebrew video suite for game consoles
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
RPG dice roll simulator for vintage Tandy TRS-80 100/102/200 laptops
A tool for creating voxels for the DelphiDoom Engine
Data-oriented and data-driven game engine written in Rust
A 2D game engine and level editor
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
8-bit Graphical API for Java
Cessna 208B Grand Caravan for Flightgear Flight Simulator