Bulletstorm Walkthrough - Act 5 - Chapter 3: Part 4
1Full Walkthrough: http://www.gamefront.com/bulletstorm-walkthrough/
When you get behind the gunner, provide covering fire for Ishi on foot. Take out the flaregunners below, but watch out for Vultures in the air too. Hold LT right before you are about to be punched by the Hekaton.
Once Trish gets behind the head of the Hekaton, aim for the red gash. When Trish gives you the word, shoot through the windows to your right, then hold LT. Take out what enemies you can below, then shoot for the back of the Hekaton's head again.
Some more Vultures will show up----take them out. A final shooting spree at the Hekaton's head should finish it off. Shoot and destory General Sarrano's location when you circle back for Ishi.
Full Walkthrough: http://www.gamefront.com/bulletstorm-walkthrough/