Descent 3 by Outrage Entertainment
fheroes2 is a recreation of Heroes of Might and Magic II game engine
3D Game engine with editor
Chess analysis, training and testing for Windows.
Cross-platform 2D game engine (+ full OpenGL, +full OpenGL ES )
FreeCS is a free-software reimplementation of Counter-Strike 1.5.
Children's learning programming language Karel the Robot in 3D
Javascript Canvas Framework
Genealogy software
Clone of Urban Assault with new Graphics.
A web port of the classic Eamon adventure RPG
Simple data driven web based gamebook engine using javascript.
Mahasona engine is an open source game engine.
Engines for Batch Games
SuperWikia: The Runtime/Realtime Environment for Codesmiths
Open source, moddable game engine for the "Polygon Love 2" game
A Wargame
RTS RPG hybrid game with realistic army and combat management.
Misfit Cubed is a mod of Misfit3D that includes an MD5 exporter
Make games with Lego-like building blocks