Flexible level editor
Ct.js is a desktop game engine that makes learning programming fun
JPHP - an implementation of PHP on Java VM
Low-Level Game Engine for Retro Platforms
Libraries for CPC game development under z88dk and SDCC
MMORPG
Performance enhancement API for RPG Maker XP, VX, VXA.
StarlingPunk is a framework built on top the Starling library
Access to Irrlicht Engine SDK from assembler, C, Python, Basic, Pascal
flixel is a free Actionscript (Flash) library
Isometric engine for 2D rendering with XNA and SDL