Mouse seems to have no affect for looking around. I see angles other than straight ahead view in the pictures otherwise I'd as "Is this a strafe only game?". I tried the 64bit version on Windows 7 64 Pro.
Is a bug in my code that I will try to fix in the future, if I find some time for it (now I'm working on the next practical exercises of the master degree).
Try this. Change the mouse sensitivity in the settings from main menu or in game pause menu, and try again. A friend reported me the same problem and is how he said that he solved it. Hope this can help you.