The source code for several atari 7800 games has been released (dig dug, xevious, commando, etc...). But that's not all! The SDK, and some tools were released too. But you'll need an Atari ST to run them
![Very Happy :D](./images/smilies/icon_e_biggrin.gif)
http://www.programmerfish.com/source-co ... -released/