I have both the background and the layout set to 960x640.
My browser isn't zoomed.
Another weird thing is the mouse pointer reacts as if the player was in the center of the larger box, so I can have my pointer to the upper right or where I see the player, but since this position is to the lower left of the center of the larger box, he turns to face the lower left.
It also displays my score in the very upper left corner on the white area.
The red circle indicates the position of my mouse at the time of the screenshot:
<img src="http://i40.tinypic.com/2d12qef.jpg" border="0" />
This is using Firefox, btw.