Construct engine

Introduction
Construct is a free powerful and easy to use development software for both DirectX 9-based games and applications. It includes an event based system for defining how the game or application will behave, in a visual, human-readable way - easy enough for complete beginners to get results quickly. Optionally, advanced users can also use Python scripting to code your creations.

Construct is not a commercial software project, and is developed by volunteers. It is 100% free to download the full version - no nag screens, adverts or restricted features at all.
Features
Create games and applications with:

    * Super fast hardware-accelerated DirectX 9 graphics engine
    * Add multiple pixel shaders for special effects, including lighting, HDR, distortion, lenses and more
    * Advanced rendering effects like motion blur, skew and bumpmapping (3D lighting)
    * Innovative Behaviors system for defining how objects work in a flexible way
    * Physics engine for realistic object behavior
    * Place object on different layers for organising display, parallaxing, or whole-layer effects - also freely zoom individual layers in and out with high detail
    * Debugger giving you complete control over all aspects of your game for testing purposes.
    * Python scripting for advanced users - however, Construct's Events system is still powerful enough to complete entire games without any scripting.
    * Smaller, faster specialised runtime for applications
    * 60+ plugins ranging from Tiled Background to Windows controls and a C++ plugin SDK for custom development

Development process
Construct is developed open source under the General Public License (GPL). This means you can download and use Construct for free, but it also means that the underlying source code - the code that defines how the program works - is also freely available. This means other programmers are free to fix errors in the code and make their own contributions to Construct. Development is located on Construct's SourceForge.net page.

For more information, see Open-source Software (Wikipedia) and GPL (Wikipedia), the open-source license Construct uses.
User Interface Library
Construct uses the Prof-UIS professional user interface library, with kind permission of FOSS Software, Inc. Remember if you wish to use this library in your own project, you must purchase the appropriate license from the website.