Bulletstorm Walkthrough - Act 3 - Chapter 2: Part 1
3Full Walkthrough: http://www.gamefront.com/bulletstorm-walkthrough/
The best spot for cover during this ambush is the huge concrete slab right behind the Dropkit. From there, aim and shoot for the red gas cans on the upper levels to do maximum damage. Eventually, you will have to move, but make sure to stick to the perimeter of the area.
The best gun to use here would be your Screamer. Charge it up and unleash a flare to kill multiple enemies at once. If you don't have enough juice, log into the Dropkit and get some.
After you take care of the guys on the upper level, they'll find their way down to you. Take care of them, log back into the Dropkit if you need any extra ammo and follow Ishi through the hole in the wall.
When you reach the drawbridge, press X on the lever to lower it. Kill the enemies on the other side and head upstairs (use the Dropkit if you need to). Pull up on the lever to use the elevator.
Exit the elevator and kick the orange panel to get downstairs. Open the door and hold LT when prompted to. Take out the enemies (might I suggest the Boneduster?) as you make your way around the catwalk.
Once you get to the lift with Ishi, pull up the lever to lower it. Kill all enemies in this area. If you kick a guy into those burning flames, you'll get a "Man Toast" kill. Clear the area to finally meet Trishka.
Full Walkthrough: http://www.gamefront.com/bulletstorm-walkthrough/