This game runs really slow on this site because of the banner ads. If you have ad blocking software (Like AdBlock Plus for Firefox) you can block the ads and it will run fine.
Had a good run keeping two corners up and joined, like a crescent moon.. then I got swarmed by like 5 fireflies and 2 bees, and then and only then, when my net broke.. did a bat pass through that area..
As other's have said, use the Pancor jackhammer (the high end auto-shotgun) and spend the rest of your xp on base/player health. Just spray when they get near, and the achievement will be easy.
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