A retro game engine for Python
3D game engine/framework in C, with Luajit and Python bindings now
GemRB is a portable open-source implementation of the Infinity Engine
An isometric arcade-style game of skill, puzzles and exploration
A cell-based puzzle game featuring classic and completely new puzzles
SDL based generic 2D game engine
Injectable LUA scripting system, SDK generator, live property editor
2D game development library for Ruby and C++
A simple tool to allow Chessmaster 10/11 bot customizations
Javascript library for making tile based games
a UCI chess engine
2D Game Engine
A cross platform Lua based game engine
A 2D game engine and level editor
A cross-platform 2D game engine
Real-time RPG for PC/tablet/phone; multiple quests and random dungeons
scriptable game engine with built-in support for 2D graphics and sound
Flexible and easy-to-use 2d game engine
Multi-platform game engine similar to old Megaman with a stage editor
Mahasona engine is an open source game engine.