Hi there I bought Back to the Future on Steam. I have a 2008 Mac Pro with ATI Radeon HD 4870 graphics card. I am getting graphics corruption issue where parts of textures are randomly flashing black. I get the same issue while playing the game in Mac OS X and Windows 7 (running natively via bootcamp). I can't seem to be able to take a screenshot of the problem because every time I do so, the screen shot comes out fine.