At first I thought this game would be really awesome but I was kind of wrong. It is only a one time fun game to me, but there are people that need to have high scores on all games they play.
If you do make a new game in the future, add more detail to the game. like what others said; upgrades, different events, landscape, possibly some zombies, and custom characters. If you add things to make people play more it will be a great game. So far, just a one time play because I know there isn't anything up ahead.