Halloween flash game, zombie killer

We are on a tight budget so pricing in on our mind as well as quality work. It's fine to use an exsiting game you have and tweak. We need a halloween flash game that is a zombie killer FPS, we have two other characters besides the zombies that we want in it, we have all the graphics. This flash game needs to have a bridge to Joomlas registration. This game needs to have registration (bridge to joomla registration) and high score. I may contract the joomla bridge out to someone else.