Our lens flare class uses an occlusion query to test visibility. They work perfectly in a windowed context but flicker on and off, and generally act unpredictably in a fullscreen window. Two .bat files are provided to launch the game, one in windowed mode and one in fullscreen mode:
Due to the differing behavior between windowed and fullscreen mode, I believe this is a driver bug.
OS: Windows 8.1 64-bit
GPU: GEForce 780 GTX