Desert Z Demo

Game for Animation Class. We're required to make it playable in all ways shapes and forms. But that's not working out well here. I've tried everything everyone has told me to try, so now I turn to YOU, viewers of my Deviantart page... Even those it's been here for less than a week.
The problem we're having is that the Zombies, your enemies, after you die still spam across the screen. This doesn't make us too thrilled. And to top it off, the Game Over Screen is still there even AFTER we go back to the main menu.

EDIT: It's the full game now! YAY . Even though it still has the same maaaaajor ass problem.

The link to the code used in game is here: [link]
Thank you for your time.