There is an issue that isn't just on the PC. Apparently, when you go on this main mission and try to chase after a certain character through a door, a loading screen activates and stays there. It goes through an infinite loop. I've tried different methods like reinstalling the game, deleting the files in the Steam folder, updating the video card drives, and trying to use Windows 7's compatibility mode and bring it down to XP. Nothing works. I'm guessing we'll have to wait for a patch to fix this issue, because the game is pretty much unplayable since I can't finish it.