RetroArch is a frontend for emulators, game engines and media players.
Machine Language Monitor for Commodore VIC-20
Game engine supporting many 3D/2D formats and graphic effects
JavaScript framework to build game engines, games, emulators and apps
Cross Platform GUI Toolkit
Cerberus Content Management System
3rd Party Video Games Developer: MetalManGames, titles of games
Free 32/64/16-bit multi-platform Pascal and Object Pascal compiler
2D Game Engine
A cross-platform interpreter for many point-and-click adventure games
Bulk call generator for Avaya
Multi-platform game engine similar to old Megaman with a stage editor
Make robots for MediaWiki-powered sites!
Portable Pokémon Mini Emulator
Cross platform Game Creation Software
I am working on upgrading the XNA Platform Game Template.
3D Engine technology with partial tools developing kit.