Loom SDK!

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.

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.

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.

The Atomic Game Engine features a cross-platform editor with deployment to Windows, OSX, Linux, WebGL, Android, and iOS. Applications can be built using JavaScript, TypeScript, native C++, and C# scripting is in development. The Atomic Game Engine is a full source solution under the permissive MIT License on GitHub

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.

The 10Duke SDK has already been used by companies worldwide to create digital ad campaigns, video sharing services, mobile marketing campaigns and much more. If you can dream it in Java, the 10Duke SDK will help you deliver it - quickly, more cheaply and on a solid code foundation. With an extensive feature set, the 10Duke SDK is the Swiss Army knife of Java application development.