If you're experiencing this problem, enter the game's Options from the main menu and go to Graphics.
Turn the Shaders slider to the lowest setting. You only need to do this once, but...
If the visual problems reappear after a few minutes of play, you will need to do the following every time you launch the game:
Go to the Graphics options through the main menu, click Resolution, switch to any resolution with a 16-bit color depth (for instance 1024x768x16 or 1440x900x16) and then switch back to the desired resolution with a 32-bit color depth (like 1024x768x32 or 1440x900x32).
The game should work without problems now, so long as you switch resolutions to 16-bit and 32-bit every time you launch it.