The BEST game / app development engine Corona SDK is rebranded as Solar2D!
Solar2D is fully open source with the MIT license. It is simply the most mature and easy to use 2D game and application development engine available. Developing with Solar2D is much faster than any other SDK because of the simplicity and ease of use of the powerful API and Lua language.
Solar2D – Light Speed Development for Everyone!
Check out Solar2D.com!