It was a really good concept. I liked it!
Things to change would probably be more interactivity. There were only really 3 buttons I could use, so it would be nice to maybe try & cater more to the various people.
Also the art could be improved. At least some color other than white & blue would be nice. Maybe animations, but all this could be way down the line.
Then either difficulty settings, or multiple levels. Maybe even upgrades (There I go again thinking too big for a prototype, haha)
Either way, I think it's good & should be improved upon.