Free and Open Game Programming Language for Windows and GNU/Linux
Cross-platform 2D and 3D game engine
An isometric arcade-style game of skill, puzzles and exploration
Ze Text Adventure game Builder : Create as you play !
Asphyre is a cross-platform framework for Delphi and FreePascal.
JavaScript framework to build game engines, games, emulators and apps
Open Source Virtual World and MMOG Development Platform
3D .NET engine for Windows, Linux, Mac
Sourceport of the classic Descent Level Editor
Built to be ease of use, with no programming knowledge, Multi-platform
Old-school 2D game engine
Java Settlers
INSTEAD - Simple Text Adventure Interpreter.
Perl bindings to the Modern OpenGL API
PyCAPGE - Python Classic Adventure Point and Click Game Engine
Processes dialogue text files exported by the Bethesda Softworks SDK