I am on the development team for Zombie! Zombie! Zombie! HD (Zx3 for short). We're looking to rework the balancing of the levels to make them scale better as players progress through the game. If you are playing Zx3 and are interested in providing us feedback, please reply to this post and/or email me at [email protected] There is a link to get the game on our Facebook page (/zombietimes3).