To defeat the Thunderhead you need to expose its weak spots. Every time it loses all HP, it gets stunned for some seconds. It has no effect shooting at it when it is stunned unless you do it at the weak spots. The weak spots are red nodes hidden behind its front legs, destroy them. The video walkthrough shows you how to destroy the boss. The Thunderhead is the last objective of mission 6, Jailbreak. It was played at difficulty Level Maverick at this video walkthrough.
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