Why does everything have to have a point to it? You're a giant monster rampaging through the city, now destroy stuff and have fun. How's that for a point?
Ok an even easier way to get the Hell Dining badge. I seriously think that with my method this is by far the EASIEST badge on Kongregate. Buy 3 Quake Boxes and upgrade them and then blow the rest of your money on Gunman. No need to upgrade your wall, they won't even reach you!