There was a graphic glitch in some early versions of the game. Go to the menu screen and look in the lower left corner. The version number is displayed there. The glitch was in some v1.00 games, and the latest version as of this writing is v1.01.

You can also verify that you have the glitch by checking the game log (look here to see how to access it). If your game has that glitch, there will be an error that says something like this:



You can download the latest update (for the Windows version) for free by downloading the demo and installing over your current game. You must download the update from the same site where you originally purchased the game, since the registration codes from each site are not interchangeable. Download the trial version and install it in the same location where you have v1.00 installed.