NICE. I'm decent at it, but this is really good. Addicting too, I like how you can add guys to help you :D. It would be awesome if you could share the source, but if not that's fine :D.

What code (If you're willing to share) did you use to make it so the zombies move towards you? I've tried a few ways to make them calculate the angle between you and them, but can't seem to get it right.