Pretty cool, I remember there was another game just like this where you had to balance upgrades with supply/demand and compete against another restaraunt. I don't want to say that you plagarized or anything, so instead I will just suggest that you carry on with something more unique in the future.
I think you could fix a couple of things like blacking out the levels player has completed, I think there's a certain psychology in "LEVEL COMPLETED" that makes aplayer feel satisfied with his achievements in the game. Also, I understand I can't upgrade the restaurant with customers inside, but I also can't do it when they're in the opponents restaurant or on the screen at all? Hmmm...
Overall I think the game is a little cramped and could use some more unique features than the other one i had mentioned.