How do you tell what floor you're on? And, as a suggestion, maybe consider smoothing out the transition between attacking different enemies. Once one dies, there's an awkward pause where if you don't click on the next target immediately you don't do anything.
Wow, that's quality flash. I am impressed by the look of the game. Although this game is obviously for a lower age demographic it sure is worth the play. And who doesn't need a little flu awareness?