Self-hosted game stream host for Moonlight
Open source clone of the Age of Empires II engine
A free/open source client and automation tool for Ragnarok Online
Source code repository of the FreeOrion project
Powerful, mature open-source cross-platform game engine for Python
Code for Cicero, an AI agent that plays the game of Diplomacy
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
Doom-based AI research platform for reinforcement learning
4X Space Strategy Game
For exploring cellular automata like Conway's Game of Life.
Cooperative multiplayer graphical RPG and adventure game
Realism Invictus mod for Civilization IV
GemRB is a portable open-source implementation of the Infinity Engine
Vivid3D is a C++ IDE/3D engine, with python scripting.
Janken - A Simple Rock, Paper, Scissors Game
Real-time collision detection and multi-physics simulation for VR
Procedurally-Generated Game-Like Gym-Environments
DOOM / Heretic / Hexen source port with enhanced graphics and UI