Play Demo button leads to black screen with 'full screen' selected.

I downloaded the demo, and was in the process of setting it up.

Under "Options" in the launcher I clicked "Full Screen." I expected the screen to switch to full and to be able to see the launcher.

The screen went full, but it was all black. Command-Q closes the game.
When I go back into the game, the launcher has a regular small screen, and when I click "Play Demo" the screen goes to full, but all black.

I tried alt-f11 as suggested by some of the other posters, but this has no effect on the screen.

Any way to send a command to switch it back to not full screen? I don't care if it is in full screen or not, I just want to try it out.

Thank you!

ps - I am using Safari Version 5.0.6 (5533.22.3)