Ok first for the easy badge just put tons of dart towers in the front and work your way into the back as your doing so upgrade your dart towers (pircing upgrade only). Then in the middle get a boomerang tower and upgrade it first with the multi target one then the sonic boom. After that keep going with the dart towers and upgrading (pircing upgrade only).
I only have a guide for the easy badge. Chow!
plz post your guide if you have one