mGSTEP port of the Cube game engine
3D playground built on three.js and cannon.js
KlayGE is a cross-platform open source game engine
RPG dice roll simulator for vintage Tandy TRS-80 100/102/200 laptops
A 2D game engine and level editor
A cross-platform 2D game engine
Planimeter Game Engine 2D - LÖVE-based game engine for Lua
IGS Labs
A cross platform Lua based game engine
A fast, scalable, distributed game server engine/framework for C++
Cross-platform 2D and 3D game engine
Opensource Game Studio
Android OpenGL Game Engine
Free and Open Game Programming Language for Windows and GNU/Linux
Blueshift is a cross-platform 3D game engine implemented in C++
Low-Level Game Engine for Retro Platforms
Real-time RPG for PC/tablet/phone; multiple quests and random dungeons
Portable game engine with main focus on point-and-click adventures
A project to create a blazingly fast Swift game engine
lightweight multi platform game engine