Construct is a free, open-source game development program that allows you to quickly and easily put together games in a drag-and-drop environment. Using the event sheet editor, you can define your game's behaviour programming-free with events, or you can use Python scripts to control it instead. It is based off a powerful hardware-accelerated DirectX 9 rendering engine with support for pixel shader effects, physics, layers, a debugger, and plugins for advanced features. There is also support for some 3D features.
