Awesome idea and as was said by others really easy and addictive controls. However I'm not sure if those zombies were meant to do anything or just be an obstacle. It would be cool to add more things like more scenarios (different locations or events, maybe some natural disasters. Also besides timer which would be cool Maybe you could throw the drinks at the tables and completing the orders? Too bad the people were solid obstacles and not move and fall when you bumped into them. Maybe even if you would add some kind of scoring system together with the timer and then based on your performance you would get paid.
Regardless you have a great, fun and addicting game that is good looking and great sounding. Nice job!