Wow there's actually one other person other than me on this planet that still has a 4:3 screen :P
I did notice that the main menu screen is messed up.
However the main game itself works fine once you get into the game as far as I can tell. Is the game not working for you at all in the 4:3 resolution?
Also what resolution are you running at. I'm running 1600x1200. Maybe you're running too low a screen resolution?