Unofficial Github host for the recently open source Quadrilateral Cowboy
https://twitter.com/BlendoGames/status/761610847852466176
Quadrilateral Cowboy uses the idTech 4 (Doom 3) engine. The source code is written in C++ and includes the solution files for Microsoft Visual C++ 2010. https://en.wikipedia.org/wiki/Id_Tech_4
The source code is released under the GPL license. https://en.wikipedia.org/wiki/GNU_General_Public_License