GLSFcave is a port of SunFlat's SFcave for UNIX/OpenGL. SFcave is
a game where the player controls a ribbon to avoid hitting walls.

You have only one control: when you hold the mouse button, the
ribbon goes up. Otherwise the ribbon goes down.

The game uses OpenGL for drawing two-dimensional frames. This is
for portability(for MacOS X) and to offload CPU.