Polycode is a free, open source framework for making games and interactive applications. It is available from http://polycode.org.

Polycode is well suited to making both 2D and 3D games as well as non-game applications. The framework provides an IDE for both world editing and writing Lua code. Polycode runs on all major platforms. The Polycode website has a section for learning how to use the framework at http://polycode.org/learn/.