Injectable LUA scripting system, SDK generator, live property editor
A development environment focused on modding
Multi Theft Auto is a game engine
Skript is a Bukkit plugin which allows server admins
Fast, small, safe, gradually typed embeddable scripting language
Cross-Platform C++ 2D/3D game engine
Open source clone of the Age of Empires II engine
Doom-based AI research platform for reinforcement learning
3D game engine/framework in C, with Luajit and Python bindings now
An open source C++ game engine
Cross-platform, open source, and super fast MUD client with scripting
A lightweight game server framework implemented with Actor Model
Simple and light-weight 3D game engine
Flax Engine, multi-platform 3D game engine
Open Source Fan-Based EverQuest Emulator Server project
Open source reimplementation of GTA San Andreas game engine in Unity
Opensource crossplatform Fallout 2 game engine writen in C++ and SDL
A greedy game engine for greedy programmers
For exploring cellular automata like Conway's Game of Life.
Cerberus Content Management System
Cross-Platform Level Editor for Doom3 and The Dark Mod
3D modeler, 3D game maker, 3D demo maker
Delphi : VRCalc++ OOSL & + (Paged List, TextEditor, VRAstroVision ...)
A fantasy roguelike game with graphics tiles.
A free 3D game engine to create games and realtimes scenes for Windows