This belongs in another section of the site, but the key is to bring down his shield which is being upheld by green areas on each of his sides, front, rear, left, and right. Specifically target the areas with green boxes and you will bring his shield down. Once his shield is down, continue keeping your distance and knock him dead with long range weapons such as the reticle and Zoomy missles. Your special, if homing or long range, is very useful as well. You might want to utilize firing homing missiles and fire missiles to the rear of you.