Duality!

Godot is a fully featured, open source, MIT licensed game engine. It focuses on having great tools, and a visual oriented workflow that can export to PC, Mobile and Web platforms. It is a cross-platform 2D and 3D game engine and game development IDE.

GDevelop is an open source game creation software, allowing to make games for the web (HTML5) or for Windows and Linux. No programming or coding skill is required! It is easy to use and powerful enough for advanced users.

Scirra Construct is a 2D game development engine with a focus on building games visually. No programming is required though the software uses a visual method for event handling that relies on programming concepts like variables, loops and conditions. It provides a powerful form of scripting that's as easy as clicking, dragging and dropping.

Polycode's core is written in C++ and currently runs on Mac, Windows and Linux with iOS and Android support planned in the future. All platform-specific functionality is abstracted into a cross-platform core and implemented natively on each platform, so the same C++ code will compile on each supported platform out of the box.

Stencyl is the creator of StencylWorks, a tool that has enabled creators of all all skills levels create iOS and Flash games in no time. In 2012, Stencyl will expand into Android and HTML5 game publishing.

Continuing the legacy of Mark Overmars' Animo and Game Maker, GameMaker: Studio is a proprietary game-creation system which can export to multiple platforms including Windows, HTML5, Linux, iOS, Mac and Android.Often considered the fastest and easiest-to-use cross-platform game IDE technology, GameMaker: Studio allows developers to create games in a single codebase and then publish them to run natively across a wide number of mobile, desktop, and web platforms.

Libgdx is a Java game development framework that provides a unified API that works across all supported platforms.

One framework for creating powerful cross-platform games. The spiritual successor to XNA with 1000's of titles shipped across desktop, mobile, and console platforms. MonoGame is a fully managed .NET open source game framework without any black boxes. Create, develop and distribute your games your way.

Construct Classic is a free, DirectX 9 game creator for Windows, designed for 2D games. It uses an event based system for defining how the game behaves, in a visual, human-readable way - you dont need to program or script anything at all. Its intuitive for beginners, but powerful enough for advanced users to work without hindrance.

The RPG Toolkit is a free, open source project delivering a simple, flexible and powerful tool for the creation of role-playing games on your personal computer.

Open RPG Maker is a free and open source clone of features from the RPG Maker series (i.e. rpgmaker200, rpgmaker2003, rpgmakerxp), as well as many other features. All of the data files are in XML format and are easily editable with any text editor.

[Multimedia Fusion 2 has been replaced by Clickteam Fusion 2.5.]