Dark Basic Pro is an open source BASIC programming language for creating Windows applications and games
Dagon is a game engine especially tailored for adventure games and based on open technologies. Featuring a simple scripting language, blazing fast performance and high portability supporting Windows, Linux and Mac OS X, the project aims to become a reference of the genre.
A 3D game engine created by Valve in 2004, and has been used by Valve, third-party companies, and countless community mods by people around the globe
The ABARE ENGINE is a powerful, feature-rich tool built for developers who require top-tier performance and flexibility in their 2D games.
Cross-platform, graphics API agnostic, "Bring Your Own Engine/Framework" style rendering library.
BYOND is the community for making and playing online multiplayer games. Make your own game with an easy-to-learn language, built-in online support, tools for developers, and plenty of articles and tutorials.
Battle tested 2D game engine with an accessible visual scripting system
A complete 3D authoring tool which includes all the features you need for creating games for multiple platforms
A free, all-in-one platform for game creators
A variant of Puzzlescript featuring 3D graphics, a first person perspective, and no limit on 2D pixel and 3D voxel sprite resolutions
Easel lets you code multiplayer games without coding the multiplayer. Code like all your players are in one shared world, like a singleplayer game, and Easel does the rest.
EasyRPG is a community project to create a free, open source, role playing game creation tool, compatible with RPG Maker 2000/2003 games.
An experimental web-based Game Engine to create simple interactive fiction