I didn't use an existing framework, other than OpenGL. The game engine that I'm using is my own and is something that I've been working on since 2010.

I think I was not very clear but the collision engine, rendering engine, physics engine, and graphical user interface engine have already been built and all of them make up my game engine.

What I actually built in two months includes the game design, game mechanics, the specific user interface for this game, and the graphics.