Extract assets -- might be easier to do it by intercepting OpenGL calls than by reverse engineering some proprietary binary format.

Edit: There are entire online communities dedicated to pulling assets out of old games, for who knows what reasons. A buddy of mine from school would spend entire weekends dumping assets from classic GameCube titles -- he would occasionally render up scenes from old Zelda games with global illumination and fancy material shaders, which were always kind of cool.

I've used this in the past to see how AAA games implement various graphic effects. It lets me see the textures, shader's and building of the various buffers (back, depth, etc) for an individual frame of the game. This is a great tool for learning exactly how games are put together graphically.

Debugging would be my first guess.