I beat him with "dog", 30 questions and he didn't get it, though after the 30, one of the possible answers was "dog" or a number of variations on that, so it was CLOSE.

Final conclusion :

Vader not only cannot read my mind, but has some AWFUL one liners, and also has to rely on the Burger King to give him hints.

He should have ended it after he failed to get the answer with "NOOOOOOOOOOOOOOO!"

EDIT : So far, all of you suck if you can't beat a flash game.